IRC · EV-REMOVAL OF NITROGEN AND PHOSPHOROUS IN A FACULTATIVE AND A WATER HYACINTH POND: A CASE...

Asian Institute of TechnologyBangkok Thailand

THESIS NO. EV-88-1

REMOVAL OF NITROGEN AND PHSOPHOROUS IN A FACULTATIVEAND A WATER HYACINTH POND : A CASE STUDY

Abadh Kishore Mishra

Asian Institute of TechnologyBangkok, Thailand

April, 1988

EV-

REMOVAL OF NITROGEN AND PHOSPHOROUS IN A FACULTATIVEAND A WATER HYACINTH POND: A CASE STUDY

by

Abad h «¡shore Mishra

A thesis submitted in partial fulfilment of the requirement for thedegree of Master of Engineering

Examination Committee:

Abadh Kishore Mishra

NationalityPrevious Degree

Scholarship Donor

Dr. Hermann M. Orth (Chairman)Dr. Chongrak PolprasertDr. Kyu Hong Ahn

NepaleseB. Sc. Civil Eng

LIBRARY. INTERNATIONAL REFERENCECENTRE FO9 COMMUNITY WATER SUPPLYAND SANilATiOlv (¡i?C)P.O. Cox 93190, 2509 AD TheTel. (070) 8149 11 ext 141/142

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Regional I n s t i t u t e of TechnologyJamshedpurRanchi University, IndiaDANIDA

Asian Institute of TechnologyBangkok, Thailand

April, 1988

ACKNOWLEDGEMENT

The author wishes to express his sincere thanks and profoundgratitude to his advisor, Dr, H. M. Orth for his continuous guidance,creative suggestions and encouragement throughout this study. He alsowishes to express his gratitude to Dr. Chongrak Polprasert and Dr. K.H. Ahn for their valuable suggestions and for serving as committeemembers of this study.

The author also expresses his sincere thanks and gratitudeto Dr. Kriengsak Udomsinrot for his valuable advice and discussion duringstudy period.

The gratitude is also expressed to the staffs of the EnvironmentalEngineering Laboratory and Physical Plant without whose help this studywould not have been completed on time.

Sincere thanks are also due to all friends who helped the authorin one or other way during the course of this study.

Grateful acknowledgement is extended to the Royal Danish Governmentfor granting the author's scholarship during his study in AIT.

Finally the author respectfully dedicates his thesis work to hisbeloved parents for their moral support and encouragement.

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ABSTRACT

A study was carried out in facultative and water hyacinth pondsoperating in parallel and receiving mainly domestic wastewater afterpretreatment in an anaerobic pond. After two months of experiments on thissystem, the load was increased in the water hyacinth pond by sending thecomplete flow in this pond and the experiments were continued. During bothstages, nitrogen and phosphorous were monitored at different points toobserve their removal in facultative and water hyacinth ponds.

Organic, nitrite and nitrate nitrogen removal were found much betterin the hyacinth pond whereas the ammonia nitrogen and phosphorous removalwas comparatively better in the facultative pond. Total nitrogen removalwas almost equal in both the ponds. Dissolved oxygen concentration wasalways much higher at every points in the facultative pond. However withdouble loading the nitrogen and phosphorous removal decreased further inthe water hyacinth pond.

Mean percent removal based on concentrations for TKN, NH«-N, Org-N,

NO2-N, NO3-N and TP for the facultaive pond were 37, 43, 26, -1867, -55

and 15 % and the corresponding removal rates in the water hyacinth pondwere 36, 30, 65, 14, 40 and 9 % respectively. During double loading, thepercent removal rates in the water hyacinth pond for average NO -N,

NO3-N TKN and TP were -29, 15, 26 and 8 % respectively.

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LIST OF SYMBOLS

BOD, " 5-day bio-chemical oxygen demand

cm = Centimeterd = DayFi = Influent of facultative pondFIO = At 10 m distance in facultative pondF30 = At 30 m distance in facultative pondF60 = At 60 m distance in facultative pondFe = Effluent of facultative pondha = HectareHi = Influent of water hyacinth pondH10 = At 10 m distance in water hyacinth pondH30 = At 30 m distance in water hyacinth pondH60 = At 60 m distance in water hyacinth pondHe - Effluent of water hyacinth pondin. = Inchkg = KilogramL = Literm = Meterm2 — Meter squarem3 = Cubic metermg = MilligramN02~N = Nitrite nitrogen

NCL-N = Nitrate nitrogen

Org-N = Organic nitrogen.TKN = Total kjeldahl nitrogenTP = Total phosphorous°C = Degree centigrade

Civ)

TABLE OF CONTENTS

CHAPTER TITLE PAGE

Title Page iAcknowledgement iiAbstract HiList of Symbols ivTable of Contents v

I INTRODUCTION 11.1 General 11.2 Objectives of the Research 21.3 Scope of the Research 2

II LITERATURE REVIEW 32.1 Previous Research 32.2 Nature of the Water Hyacinth 72.3 Removal Mechanism of Nitrogen and

Phosphorous in Facultative Pond 82.3.1 Nitrogen Removal 82.3.2 Phosphorous Removal 10

2.4 Removal Mechanism of Nitrogen andPhosphorous in Water Hyacinth Pond 102.4.1 Nitrogen Removal 122.4.2 Phosphorous Removal 13

2.5 Pond Efficiency 132.6 Sludge Accumulation 17

III METHODOLOGY 183.1 Source and Treatment Method of

Wastewater 183.2 Sampling 183.3 Experimental Program 193.4 Analytical Method 19

IV RESULTS AND DISCUSSION 234.1 Results 234.2 Discussion 23

4.2.1 Total Nitrogen 234.2.2 Total Phosphorous 29

4.3 Statistical Analysis of the Data 294.4 Removal Efficiency 334.5 Dissolved Oxygen, pH and Temperature 434.6 Water Losses 464.7 Sludge Accumulation and its

Characteristics 464.8 Odor Release 484.9 Foaming in Water Hyacinth Pond 50

V CONCLUSIONS 51

VI RECOMMENDATIONS FOR FUTURE STUDY 52

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REFERENCES 53

APPENDIX A - EXPERIMENTAL DATA DURING FIRSTSTAGE 59

APPENDIX B - EXPERIMENTAL DATA DURING SECONDSTAGE 70

APPENDIX C - FLOW RATE OF PONDS DURING FIRSTAND SECOND STAGE 79

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I INTRODUCTION

1.1 General

Waste stabilization ponds are the simplest and most economicalmethod, if land is cheap, for wastewater treatment to reduce organicpollution and pathogenic bacterial contamination for small communitiesand rural area, particularly in tropical and subtropical regions.Stabilization ponds are becoming more popular in developing countriesfor wastewater treatment because of relatively low energy requirementand low-requirement of skilled manpower for operation and maintenance.The water quality of effluent from a properly designed pond is equallygood as compared to any other conventional treatment process at low cost.But the most undesirable features for stabilization pond system ispresence of large quantity of algae which causes negative impact onreceiving source specially if the water is used for drinking watersupply. In tropical and sub-tropical region, the solar radiation issufficiently intense through out the year to induce and enhance the algaeblooming. Due to presence of high algae concentration in the effluent offacultative pond, the treatment efficiency is adversely affected.

Nitrogen and phosphorous compounds that are introduced intoreceiving bodies of water as part of the effluent from water facilities,stimulate the growth of the algae. The presence of profuse algal growthsin receiving water bodies is one characteristic of eutrophication. Theexcessive eutrophication of receiving water by adding the nitrogen andphosphorous enriched waste is merging a major water pollution problem byreducing the utility and beauty of water body and threatening itsexistance in course time. Ammonia nitrogen which is found in main formin domestic wastewater accelerates the eutrophication rate of receivingwaters by serving as a plant nutrient and by exerting a demand on theavailable dissolved oxygen. Nitrate nitrogen present in effluent may alsoresult the health hazard if the receiving waters are used for watersupply. Hence the reduction of both nitrogen and phosphorous inwastewater is important in controlling the eutrophication.

The aquatic plant treatment systems are becoming more popular toovercome the effect of algal bloom and as an alternative to conventionalsystem due to better treatment of wastewater at low cost and at lessmaintenance. In recent year, a number of studies have been done by severalinvestigators and reported that water hyacinth has better nutrientremoval capacity from domestic wastewater. The main function of aquaticplant is to provide support for bacterial biomass which degrade theorganic pollutant present in wastewater and reduce the algal growth inpond by obstructing the sunlight penetration into the pond.

In tropical region very few study is reported on removal of nitrogenand phosphorous from full scale facultative and water hyacinth pond. Toevaluate the efficiency of facultative and water hyacinth pond in removingnutrient was the main purpose of this research.

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1.2 Objectives of the Research

The objectives of the study were:

1) To compare the treatment efficiency of facultative and waterhyacinth pond in removing total kjeldahl nitrogen ammonianitrogen, organic nitrogen, nitrite nitrogen, nitrate nitrogenand total phosphorous.

2) To observe and compare the efficiency of water hyacinth pond dueto effect of double loading.

1.3 Scope of the Research

In this study of research, AIT waste stabilization pond consistingof a facultative and water hyacinth pond in parallel and treating domesticwaste from campus was used to evaluate the efficiency of the ponds. Duringsecond stage the load was increased in the same water hyacinth pond toobserve the effect of treatment efficiency of the system. The experimentwas conducted continuously for five months duration, for both stagesstarting from October 1987 till the end of February 1988.

Parameter measured were total kjeldahl nitrogen, ammonia nitrogen,organic nitrogen, total phosphorous and BOD . Nitrite and nitrate

nitrogen value were taken from BHAMIDIPATI (1988), to observe the removalof all form of nitrogen in pond system. Other conditions includingsampling and analysis time for nitrite and nitrate nitrogen were same asammonia, organic and total kjeldahl nitrogen.

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II LITERATURE REVIEW

2.1 Previous Research

The operation of the stabilization pond system is dependent on thevolumetric loading, BOD loading per unit area and concentration of organicmatter in the wastewater. Consequently due to settleable solid andanaerobic breakdown there is accumulation of sludge which decreases thevolume of pond and ultimately affect on volumetric loading which may causethe poor effluent quality.

Little attention has been devoted specifically for nitrogen andphosphorous reduction by pond treatment. Data are incidentally availablein previous studies about nitrogen and phosphorous removal. As wastestabilization pond treatment is more effective particular for BOD andcoliform removal, evaluation of pond is always expressed only in thesefactors.

FITZGERALD and ROHLICH (1958) reported that ammonia nitrogen andorganic nitrogen removal in stabilization pond was 75 to 90 % and 60 %respectively. Nitrate and nitrite nitrogen was increased but amountpresent was insignificant compared to ammonia nitrogen. They alsoreported that phosphorous value was reduced by 96 %,

NEEL et al. (1961) reported on general observation that nitrate isnot produced in ponds and nitrite is also absent significantly in lackof nitrification. Organic nitrogen in the waste is converted to ammoniawhich is readily used by algae and generally not oxidised further tonitrite and nitrate.

BUSH et al. (1961) reported that ammonia, organic and nitratenitrogen removal in algae pond were 63-90 %, 32-74 % and 27-60 %respectively and phosphorous removal was 19-68 %.

LOEHR and STEPHENSON (1965) reported that a normal oxidation pondis not effective to control1 the nitrogen and phosphorous from wastewater.They reported that sometimes negative removal of nitrogen was observed.However the phosphorous removal was observed during summer months and itreduced to zero in winter months.

ASSENZO and REID (1966) conducted a study on seven Oklahomastabilization pond system and reported that total kjeldahl nitrogen andtotal phosphorous removal ranged from 30 to 95 percent. They also reportedthat nitrogen fixation was not observed in any of the ponds. The greaterportion of the nitrogen in the pond was consistently in the form ofammonia which might have depressed the nitrogen fixation

ARCEIVALA (1981) reported that field ponds often show widevariations in nitrogen removal efficiencies and removal are generallyexpected to be greater at warmer temperature and higher loading.

GLOYNA (1971) reported that the rate of gas evolution from the sludgelayer is sensitive measure of the biological activity in the bottom layer

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of facultative pond. Once gas production is established, loading in pondwill be increased affecting the effluent quality.

The facultative pond which is most effective for wastewatertreatment has limitation due to large quantity of algal growth whichcauses the negative impact on receiving stream. To control the algalgrowth in facultative pond, a number of study have been done on waterhyacinth and it has been reported that water hyacinth has better nutrientremoval capacity as well as to control the algal bloom compared to freefacultative pond.

SHEFFIELD (1966), as reported by CORNWELL et al., (1977), reportedthat water hyacinth grown in secondary wastewater effluent, initiallyremoved 40 to 50 percent of orthophosphates. However after 25 to 30 daysof continuous operation, the phosphate removal efficiency decreased upto-5 to 8 percent. This was attributed to the sloughing and accumulation ofdetritus on the bottom of pond because of the non-harvest procedure. Healso reported that 94 percent removal of nitrate and ammonia nitrogen wasobserved when water hyacinth were grown in a semi-continuous recirculatedextended aeration effluent with a contact period of 10 days.

CLOCK (1968), as reported by CORNWELL et al., (1977), has found outthat high removal of nitrogen (75% reduction in nitrate nitrogen) andphosphorous (61% reduction in Ortho-P) could be obtained when secondarysewage effluent was in contact with a dense mass of growing water hyacinthat a detention time of 5 days.

ROGER and DAVIS (1972) performed an experiment for nitrogen andphosphorous removal by water hyacinth in static water and continuous flow.They reported that phosphorous removal in continuous flow was better thanstatic water whereas the nitrogen removal was almost same in bothcondition. They also reported that one hectare of water hyacinth plantsunder normal condition were able to absorb the average daily nitrogen andphosphorous waste production of over 800 people.

W0LVERT0N and McDONALD (1975) reported that the total kjeldahlnitrogen removal by water hyacinth was 60% whereas the total phosphorousremoval was 26% for the first five weeks. They suggested that waterhyacinth should be harvested at five week intervals for maximumphosphorous removal.

DUNIGAN et al. (1975) conducted the experiment in greenhouse labscale and in two farm ponds. They reported that water hyacinth was capableto remove the ammonia nitrogen from water in both greenhouse and fieldpond test, but nitrate nitrogen removal in field test was negligible.

CORNWELL et al. (1977) reported that the nutrient percent removalby water hyacinth is dependent on the detention time of wastewater in thepond, water depth and pond surface area. Fig. 2.1 and 2.2 show the percentremoval of phosphorous and nitrogen related to pond surface area and flow.They reported that in order to remove 80 percent of the nitrogen, 2.1hectares of water hyacinths were needed per 3800 m3/<L The correspondingphosphorous removal was about 44 percent.

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£

0 50 100 150 200 . 230

SA (Surface oreo p»r unil flow, thoojindj

square f*«< P*' wqill

Fig. 2.1 Phosphorous Removal by WaterHyacinth Related to PondSurface Area and Flow.

(Source: CORNWELL et al-, 1977)

loo

O SO 100 150 200 250

SA (Suffoce arid oer uni» Mo*t, Ihouiontfj offtp( pur m<jdl

Fig. 2.2 Nitrogen Removal by WaterHyacinth Related to PondSurface Area and Flow.

(Source: CORNWELL et al., 1977)

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DINGES (1978) reported that controlled culture of water hyacinthsin shallow basin was effective in removing algae, other suspendedparticles and dissolved impurities from stabilization pond effluent.Clear high quality effluent from the system was low in nitrogen and fecalcoliform bacteria. The BOD, SS and COD reduction through the plantculture were 97, 95 and 90 percent respectively. Mean effluent BOD, TSSand total nitrogen concentration were <10 mg/L, <10 mg/L and <5 tng/Lrespectively. He also reported that a significant reduction in totalnitrogen (organic and inorganic) through the system was obtained in boththe summer and winter season.

As reported by REDDY and SUTTON (1984), SWETT (1979) reported, afterone year of field experiment in Coral Spring (South Florida) that waterhyacinth lagoons can provide an advanced treatment to effluent from anactivated sludge plant by removing 67 % of total solids, 98% of BOD, 97% of TKN and 79 % of total phosphorous. In Mississippi, WOLVERTON andMcDONALD (I979) observed a reduction of 46 to 22 % in TKN and 28 to 52 %in TP from sewage effluent containing water hyacinth, while in Texas,DINGES (1979) measured a BOD reduction of 77 to 87 % and a TKN reductionof 63 to 69 % by water-hyacinth.

WOLVERTON et al. (1979) reported that the BOD and suspended solidsremoval rates in hyacinth basin are not entirely dependent on growth andharvesting rates whereas the removal of nutrients such as nitrogen andphosphorous is dependent on these variables.

The extensive works of TCHÓBANOGLOUS et al. , (1979), TCHOBANOGLOUS(1980), O'BRIEN (1981), STOWELL et al. (1981) and MIDDLEBROOKS (1980)may be referred for the design of wastewater treatment system usingaquatic macrophytes.

TCHOBANOGLOUS et al. (1979), TCHOBANOGLOUS (1980), MIDDLEBROOKS(1980) and REED et al. (1980) have dealt with the concept, design,implication, management and use of aquatic system.

MIDDLEBROOKS (1980) reported that the sludge accumulation in waterhyacinth pond was between 1.5 to 8*10* m3 of sludge/m3 of wastewatertreated compare to 1.8*103 m3 of sludge/m3 of wastewater treated forconventional primary stabilization ponds.

Most of the studies reported above were conducted for a short periodand the nutrient removal efficiency values do not include the seasonalvariability. REDDY et al. (1982) reported that nutrient removalefficiency by water hyacinth shows strong seasonal dependence, becauseplant growth is influenced by solar radiation and ambient air temperatureand biochemical transformations influenced by temperature,

STOWELL et al. (1981) studied about the treatment effectiveness ofwater hyacinth and emergent plant at different BOD loading and reportedthat aquatic system are capable of producing effluents with BODconcentration consistently below 10 mg/L.

DE BUSK et al. (1983) conducted the experiment to evaluate theremoval of nitrogen and phosphorous by water hyacinth plant, with and

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without harvesting, in seperate pond. They found that the nitrogen andphosphorous were removed at higher rates in the harvested pond (362 and115 mg/ni2/d respectively) than in the non-harvested pond (55 and 15mg/mVd respectively). Mean total nitrogen and phosphorous removal fromthe complete system were 87 % and 10 % respectively.

REDDY (1983) performed the experiment to investigate the removal ofnitrogen and phosphorous in retention reservoir with different vascularaquatic mycrophytes namely Pennywort, Water hyacinth, cattails, elodeaand control (no mycrophytes). He reported that nitrogen removal wasfaster in Pennywort and cattails system whereas phosphorous removal wasfaster in Pennywort system than water hyacinth. He also reported that 34to 40 % of inorganic nitrogen (ammonia + nitrate) was removed by plantuptake while 45 to 52 % of nitrogen was lost through ammoniavolatilization and nitrification denitrification process. Plant removalof phosphorous was in range of 3 to 65 % while 7 to 87 % of phosphorouswas lost through precipitation and adsorption reactions.

HAUSER (1984) reported that ammonia and total nitrogen removal inwater hyacinth system with aeration were 99 and 70 % respectively comparedto 70 and 55 % removal in non-aerated system.

REDDY and DE BUSK (1985) evaluated thé nitrogen and phosphorousremoval by eight different aquatic macrophytes namely water hyacinth,water lettuce, pennywort, duchweeds, azolla, salvinia and a submergedmacrophyte egeria. They found that nitrogen removal by water hyacinth washigher than other macrophytes during summer and winter whereasphosphorous removal in summer was highest by water hyacinth and egeriasystem while pennywort and duckweeds showed high phosphorous removalduring the winter.

ORTH and SAPKOTA (1987) reported that SS, COD, TKN and TP reductionthrough water hyacinth system were 81, 80, 79 and 89 % respectivelycompared to 9, 24, 47 and 16 % reduction respectively in facultative pondwithout water hyacinth.

2.2 Nature of Water Hyacinth (Eichhornia Crassipes Solms)

Water hyacinth is one of the most prominent floating aquatic plantfound throughout the tropical subtropical and warm temperate regions ofthe world. It is also one of the most rapid growing aquatic macrophytesand is ranked eight among the world's top 10 weeds. Growth rates ofhyacinth systems is a function of 1) water temperature ii) wastewatercomposition iii) efficiency of plant to utilize solar energy and iv)procedures used for plant harvesting. Nitrogen and Phosphorous areprobably the most important plant nutrients limiting the growth of waterhyacinths.The water content of water hyacinth averages about 95 % (89.3% in leaf blades to 96.7 % in stems).

C0RNWELL et al. (1977) reported that rate of growth of waterhyacinth in wastewater effluent is about twice that of reported naturalwater values. The calculated area doubling time was found to be 6.2 days.

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It is resistant to insects and disease, but very sensitive to highsalinity and low temperature and does not grow in water with a temperatureof 10°C or lower. The optimum temperature for water hyacinth growthranges between 21 and 30°C. Plants die within a matter of hours when thesurface water temperature approaches the freezing point.

2.3 Removal Mechanism of Nitrogen and Phosphorous in Facultative Ponds

2.3.1 Nitrogen Removal

"Biological treatment of wastewater in stabilization ponds involvesseveral different concepts with respect to nitrogen removal. Biologicaloxidation mechanisms in ponds are basically similar to those found in theactivated sludge and trickling filter processes. However, the cell growthnitrogen normally discharged as excess sludge from the other treatmentsystems but it either remains in the pond, which released again to theliquid or is discharged with pond effluent" (JOHNSON, 1968).

Organic and ammonia nitrogen (total kjeldahl nitrogen) are theprinciple form present in untreated wastewater. Total kjeldahl nitrogenreduction in wastewater can occur through several mechanisms.

a) gaseous ammonia stripping to the atmosphere.b) ammonia assimilation in biomass.c) biological nitrification.d) biological denitrification.e) sedimentation of insoluble nitrogen.

Ammonia nitrogen exists in aqueous solutions as ammonia (NH_) or

ammonium ion (NH, ) depending on the pH of the wastewater. The

concentration of ammonia increases rapidly as the pH rises and this bringsthe loss of gaseous ammonia to the atmosphere by volatilization. Withalgal growth, the pH value of pond water may rise above 9.5 at noon andconsiderable loss of ammonia can occur. ARCEIVALA (1981) reported thatan experiment in India showed about 40-60 ammonia nitrogen removal in oneday when the pH had been rised earlier by lime addition to 11.0. "The rateof the gaseous ammonia losses to the atmosphere depend mainly upon thepH value, temperature, hydraulic loading rate and the mixing conditionin the pond" (MIDDLEBROOKS and PANO, 1983). WILD et al.. (1971) reportedthat the nitrification is directely related to pH and temperature of thewastewater. They suggested that optimum pH for nitrification is 8.4. Fig.2.3 shows that 90 % of maximum nitrification rate occurs between the pHvalues of 8.4 to 8.9 and that outside the range of 7.0 to 9.8 less than50 % of the optimum rate occurs. SHAMMAS (1986) reported thatnitrification rate in wastewater is function of temperature within therange of 5°C to 35°C and maximum rate occurs at 30°C. WILD et al. . (1971)also reported that maximum nitrification occurs at 30dC. As shown in Fig.2.4, they found that the nitrification rate at 27°C and 17°C were 90 %and 50 % respectively of that at 30°C. Fig. 2.5 also shows the expectedrate of nitrification compared to temperature for various selected pHconditions.

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100

30

ao

70

60

50

40

30

20

10

0

H

/

AA

AT 20-C

\/s

N

I

\. .

\

6.0 7.0 a.opH

9.0 10.0

Fig. 2.3 Percent of Maximum Rate of Nitrificationat Constant Temperature verses pH

(Source: WILD et a l . , 1971)

too

TOJJ

« «Ou

""* 50

/

/

/

/

/

/ •/ pMSS

/

/

20

0 J 20 25 30 35

Temperature *C

Fig. 2.4 Rate of Nitrification at allTemperatures Compared to theat 30aC

(Source: WILD et a l . , 1971)

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Organic nitrogen contained in wastewater undergoes ammonificationand the resulting ammonia nitrogen is then partly used in new cell growthand partly converted to nitrite and nitrate nitrogen if conditions arefavorable. Ammonia nitrogen assimilation into blomass depends upon thebiological activity in the system and is affected by several factors suchas temperature, organic load, detention time and wastewatercharacteristics (MIDDLEBROOKS and PANO, 1983). The possible mechanism ofnitrogen removal in stabilization pond depends upon the growth of algaein the pond and their subsequent harvesting .

In presence of oxygen in wastewater, the ammonia nitrogen isbiologically converted to nitrite and nitrate nitrogen undernitrification process. Nitrate nitrogen, the final product ofnitrification, is lost partly due to algal uptake and partly todenitrification. Under anaerobic conditions nitrates and nitrites areboth reduced by denitrification process. ARCHÍVALA (1981) reported thatless than 20 % of nitrate nitrogen is lost due to algal uptake andremaining is lost by denitrification. In absence of algal harvesting, themajor mechanism for nitrogen removal from pond is denitrification.

2.3.2 Phosphorous Removal

The total phosphorous present in wastewater are in form of organicand inorganic phosphate (ortho and poly phosphate), the latter being 2to 3 times more abundant. The main mechanism of phosphorous removal instabilization pond are precipitation of phosphate at high pH value andabsorption by the algae. Algae plays major role in both mechanism forphosphorous removal. Phosphorous removal is expected high in warmerweather when algal activity and growth are at maximum. A considerableproportion of phosphorous is reduced by the precipitation at high pH valuecaused by cabon di-oxide consumption by algae during the photosynthesisprocess. Second mechanism of reduction is directly uptaken by algae, whichrequire phosphorous as nutrient for cell synthesis. FITZGERALD andROHLICH (1958) reported that 96% of phosphorous is removed from pond outof which 75 % is removed by precipitation and rest by algae uptake. TOMSet al., (1975), as reported by ARCEIVALA (1981), found that phosphorousremoval in the pond is directly related to pH value. Fig. 2.6 shows thatprecipitation begins at pH 8.2 and the soluble phosphorous concentrationdecreases by 10 fold for each further unit increase in pH value.

2.4 Removal Mechanism of Nitrogen and Phosphorous in Water Hyacinth Pond

The water hyacinth plants, themselves are very less involved inactual treatment of the wastewater. Their function is to providecomponents of aquatic environment that improve the wastewater treatmentcapacity of that environment. Some specific functions of water hyacinthplant in aquatic treatment system are presented in Table 2.1

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IS

Is5 ?

35

.30

.20

.15

.10

.05

0 5 10 15 20 25 30 35 40 45 50

Temperature "C

Fig. 2.5 Race of Nitrification verses Temperatureat Various pH Levels

(Source: WILD et a.l. , 1971)

1

V./

OPTIMUM RATE

75% 0

5 0 % 0

?TIMUM7.5.

'T1MUMr.o.

pH 8.'

RATE9.3

RATE t,9.0

t

H

H

10

00

HI

<3

0

01

STABLE PHOSPHATE

PHOSPHATE

V

ESTIMATED UNE OF ^ ^ \LIMITING SOLUBILITY

i

PRECIPITATES

\ |90 to o

Fig. 2.6 The Effect of pH on PhosphatePrecipitation

(Source: ARCEIVALA, 1981)

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Table 2.1 Functions of water hyacinth plants in aquatic Treatmentsystem (STOWELL et al.,1981)

I PLANT PARTS FUNCTION

Roots and stems inthe water column

Stems and leaves ator above the watersurface

I 1. Surfaces on which bacteria grow.

2. Media for filtration andadsorption of solids.

1. Attenuate sunlight and thus canprevent the growth of suspendedalgae.

i 2. Reduce the effects of wind on water(e.g. roiling of settled matter)

3. Reduce the transfer of gases andheat between atmosphere and water.

4. Transfer of oxygen from leaves tothe root surfaces.

In aquatic systems, wastewater is treated principally by means ofbacterial metabolism and physical sedimentation as is the case inconventional activated sludge and trickling filter systems. Thefundamental difference between conventional and aquatic systems is thatonal in conventional systems wastewater is treated rapidly in highlymanaged, energy intensive environments whereas in aquatic systemstreatment occurs at comparatively slow rate in essentially unmanagednatural environments.

The removal mechanism for different contaminants in wastewater bywater hyacinth are as the following.

2.4.1 Nitrogen Removal

The removal mechanisms of nitrogen in water hyacinth aresedimentation, volatilization, plant uptake and harvesting, microbialassimilation, and nitrification denitrification process. With theexception of denitrification and ammonia volatilization, theaforementioned mechanism do not remove nitrogen but rather convert oneform of nitrogen into another that can be removed. Plant uptake andnitrification are the most significant conversion mechanisms for ammonianitrogen in a hyacinth system treating a secondary effluent. Nitrogenremoval as a result of hyacinth uptake is a function of i) water hyacinthgrowth rate ii) nitrogen content of hyacinths and iii) the ¡rate ofharvesting. Harvesting of hyacinth is the main to remove the nitrogen byplant uptake in hyacinth system. Nitrogen incorporated in influent solids

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is removed by sedimentation. Nitrogen content in hyacinth tissue is alsoremoved by sedimentation if plants are subjected to seasonal dieback. Itis important to note that at least a portion of nitrogen removed bysedimentation will be resolubilized and released to the water column. Asignificant amount of nitrogen is removed by bacterial nitrification anddenitrification process. NICHOLS (1983) reported that nitrificationcoupled with denitrification, and not plant uptake, is the principalnitrogen removal mechanism. Nitrifying bacteria which is responsible fornitrification grows rapidly on submerged roots and stems of aquatic plantthan other potential attachment sites. Nitrate produced throughnitrification is removed by denitrification, which occurs in thesediments of aquatic system, and plant uptake.

2.4.2 Phosphorous Removal

Mechanism that may be important for phosphorous removal in waterhyacinth system are plant uptake, and biological and chemical storage ofphosphorous in the sediments. Chemical adsorption and precipitationreaction in sediments are the more significant mechanism compare to plantuptake. As reported in literature review the phosphorous removal in waterhyacinth system is not good if hyacinth is not harvested regularly.

The principal removal mechanism for the wastewater pollutant inaquatic treatment system employing plant are summarized in Table 2.2.

2.5 Pond Efficiency

Much concern has been expressed everywhere regarding the adequancyof stabilization pond final effluent to be discharged into receivingbodies of water. This question is directly related to the gradual changethat occurs in a series of ponds which show in many cases a deteriorationof pond performance with time, defined as aging.

SHELEF et al. (1974) performed a experiment continuously for fouryears on a series of five pilot plant-scale ponds to evaluate the designof a Dan Region (Greater Tel Aviv) wastewater treatment and reclamationproject. They reported that changes that occur from year to year in aseries of stabilization ponds result in a gradual deterioration in removalefficiency of BOD, SS, Nitrogen and Phosphorous at each pond in seriesand net effect is reflected in the quality of the final effluent of thepond. They reported that increase in thickness of bottom sludgesaccompanied by increasing anaerobiosis of lower liquid layers in thelatter ponds in the series as well as delay decomposition of accumulatedsludge seem to be some of the reasons for the "Creeping" deteriorationin performance. The increase of algae concentration in the latter pondof the series from year to year is a major factor responssible for thedecrease in the quality of the final effluent.

Fig. 2.7 and 2.8 summarizes the results of effluent BOD of each pondsand final pond respectively for a four years period. The changes in totalnitrogen and total phosphorous concentration between first two years andfirst three years are shown in Fig. 2.9 and 2.10 respectively.

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Table 2, 2- Contaminant Removal Mechanisms Operative in Aquatic Treatment Systems*

Mechanism

PhysicalSedimentation

Filtration

Adsorption

Volatilization

ChemicalPrecipitation

Adsorption

Decomposition

BiologicalBacterialmetabolism1

Plantmetabolism'

Plantabsorption

Naturaldie-off

Contaminant Affected*

*£>ISID a4J-H4Ji-(0) 0MM

P

S

•—Í

10•o

o-o•-l-rt

i-l t-l

0 Ooco

S

S

S

p

ooca

I

P

c

oLi•rt

I

S

p

s

m3QL,0Xia.W0JSOt

I

P

P

S

als

w

>a)a>

I

p

p

s

XIa«a•Ht.<u m•u P

V U10 .H

I

S

P

P

S

S

>.o nJJ OO-*10 Ct. 10(u Di

a o

I

P

S

P

Description

Gravitational settling of solids(and constituent contaminants)in pond/marsh settings.

Particulates filtered mechanicallyas nater passes through substrate,root masses, or fish.

Interparticle attractive force(van der Raals force)volatilization of HB3 from theRastevater.

Formation or co-precipitationnith insoluble compounds.

Adsoption on substrate and plantsurface.

Decomposition or alteration of lessstable compounds by BV irradiation,oxidation and reduction.

Removal of colloidal solids andsoluble organice by suspended,benthic, and plant supportedbacterial. Bacterial nitrificationand denitrification.

uptake and metabolism of organice byplants,Root excretions may be toxicto organisms of enteric origin.

Dnder proper conditions significantquantities of these contaminantsHill be taken up by plants.

Natural decay of organisms in anunfavorable environment.

'Adopted from STOHELL, et al., 1980."P = primary effect, S = secondary effect, I = incidental effect (effect occurring

incidental to removal of another contaminant).'The term metabolism includes both biosynthesis and catabolic reactions.

-15-

Detention Time (days)

Fig. 2.7 Yearly Changes in BOD as a

Function of Detention Timeand Sequential of Pond

(Source: SHELEF et al., 1974)

Ota

irt 4 0 -

Year of Pond Operation

Fig, 2.8 Changes in the BOD.

as a Function of Time

(Source: SHELEF et al., 1974)

-16-

•îO

zS,oovT

?. 40

Is

liu

zo

0

•s

Pond No1

— — •

) \ :

' • / •

! ' •

; • '

' / -

•?:?

i:í;.j-

-s.

fflaw

— —Omoived Nitrogen F7]

Nilroqeri in susoenaed t~^lï«vf mailer [ . - j

i I I Yt

;Í5:;

lili;»

:.'f.:

f

i«r r^T?'•??•

• ! ^ : : " .

• • : f

lilyt». y.:C - -.

• :v

h-'mg-;;%,

&.'

¿rtdvf

. . • M I * 2p<j ï»

il: •

2MVÍ

1 ir Vf

•> . ; •

i \lu

' ïï ? Œ 3Z

Fig. 2.9 Changes in Nitrogen Concentration in the..First and Second Year of Operation alongthe Series of Pond

(Source: SHELEF et al., 197¿)

so

I5c

I 2̂ W

Õ

c

Pond No Row

Oisiolved

J, m suSDendtd mailer f I

-.1

Itir.

"•;!•;•;

Mfel

• • x \f

II:.-|!

1•f::S;i

i .d.i

Ulr,

fi

i: / ' •

• • i : :

' U y*

3rayr

•U IX.

v

_ _

. - •

Fig. 2.10 Changes in Phosphate Concentration in CheFirst and Third Years of Operation alongthe Series of Pond

(Source: SHELEF et al., 19 74)

-17-

2.6 Sludge Accumulation

A certain amount of sludge accumulation occurs in stabilizationponds over a period of time. The addition depth to be provided in a pondshould be sufficient to take care of the likely accumulation by the timethe pond becomes due to desludging. Sludge deposits accumulate in ponds,remain anaerobic throughout their depth and are almost entirelyresponsible for the removal of carbon from the pond environment. Thesludge deposits are a results of 1) suspended solids present in theinfluent wastewater, 2) bacterial solid synthesized during the metabolismof the organic wastes and 3) algal solids synthesized duringphotosynthesis. The mechanism responsible for sludge deposition are: 1)sedimentation of influent suspended solids, 2) bioflocculation of algaland bacterial growths in the presence of molecular oxygen and 3)autoflocculation of algae, bacteria and organic detritus enmeshed byfloes particles formed due to increases in temperature and pH.

MIDDLEBROOKS et al.. (1965) studied several facultative ponds inMississippi and found annual sludge accumulation rates of 1.5-5.1 cm(0.6-2.0 in.). GLOYNA (1971) reported that the sludge accumulation on pondis at rate of 0.03 to 0.05 in3 per person per year, SCHNEITER et al. , (1981)studied several facultative pond in Canada and Alaska and reported thatsludge accumulation rates varies from 0.25 to 0.40 m3 per 1000 people perday.

Pond cleaning interval depends on the population served by unit areaof the pond and the depth provided for sludge storage. ARCEIVALA (1981)recommended the cleaning frequency of once in six year in India where pondloading are high and contains heavier grit load, but according to MEIRINGet al., (1968) the pond should be cleaned out after 9 to 12 years ofoperation for better performance.

-18-

III METHODOLOGY

3.1 Source and treatment method of wastewater

Wastewater produced in AIT is treated by its own stabilization pondsystem. The pond system is designed in two parallel way, each oneconsisting of an anaerobic pond followed by a facultative pond as shownin Fig. 3.1. The facultative ponds recieve the wastewater from AIT, afterpretreated in anaerobic ponds, and the effluents are discharged to nearby canal. These both facultative ponds were selected to conduct theexperiment.

In September 1986, water hyacinth was planted in one of thefacultative pond to study the comparative performance of the ponds, withand without the water hyacinth. That pond was full of water hyacith infirst week of January 1987. In June 1987, almost 50% of pond waterhyacinth was harvested manually, from influent side. Before starting thisexperiment, the water hyacinth was again planted to cover the open watersurface with hyacinth. In the first week of November 1978, water hyacinthwas planted in one of anaerobic pond (hyacinth section). Eventhough itwas beyond the scope of this study, the influent and effluent fromanaerobic pond were analysed to observe the effectiveness of plants forprimary treatment. That anaerobic pond was full of water hyacinth inmiddle of February 1988.

The flow rate of facultative pond and water hyacinth pond werecontrolled by V-notch (90°) weir so that the facultative and waterhyacinth pond recieved almost equal hydraulic loading. The influent andeffluent flow rate were measured, throughout the experiment period, withexisting V-notch weir at outlet of all four ponds used with automaticlevel recorder.

3.2 Sampling

Grab samples were collected from influent, effluent and at 10 m,30 m and 60 m along the pond in both systems. The sampling points infacultative and water hyacinth pond are shown in Fig. 3.2. Altogetherfive samples were taken from each ponds. Boat was used to collect thesample along the facultative pond whereas in water hyacinth pond temporarywooden foot path were constructed (Fig. 3.2). 1 liter sampler was usedto collect the sample from the middle of the ponds, to avoid thedisturbance by boating and movement on foot path. Influent and effluentsamples were collected at effluent chambers of anaerobic and facultativepond respectively. Every time samples were collected about 10 to 15 cmbelow the wastewater surface level. The frequency of sampling was afterevery two or three days according to availability of time, and samplingtime was kept on changing, from morning to evening, to get average dailyrepresentative data. When the facultative pond was complete dry, thecomposite samples of sludge were collected from three different sectionof facultative pond for their analysis (Fig. 4.24).

-19-

3.3 Experimental Program

To evaluate the performance of the pond, according to requiredobjectives, the experiment was conducted in two stages as described below.

(i) First Stage :- In this stage, experiment was started from first weekof October 1987 till first week of December 1987. During that period,every time ten grab samples, five from each pond, were collected andanalysed immediately in Environmental Engineering Laboratory for thefollowing parameters: 5-day biochemical oxygen demand (BOD_), ammonia

nitrogen (NH3-N), organic nitrogen (Org-N), total kjeldahl nitrogen

(TKN), and total phosphorous (TP). The physical parameters such asdissolved oxygen, temperature and pH were also measured. The dissolvedoxygen and temperature were measured at situ by membrane electrode andportable DO meter whereas pH value was measured by pH meter in laboratory.

(ii) Second Stage:- After first stage, total flow was diverted toward thehyacinth pond in second week of December and experiment was continued tillthe end of February 1988. During that period altogether six samples, fivefrom hyacinth system as mentioned earlier and one from anaerobic pond,were collected and analysed for the following parameters: 5-daybiochemical oxygen demand, total kjeldahl nitrogen and totalphosphorous. Dissolved oxygen, temperature and pH were measured by samemethod as in first stage. The influent and effluent of hyacinth pond wasanalysed for detergent, to investigate the reason of foaming in waterhyacinth pond.

During second stage there was no flow in facultative pond. After oneweek, the wastewater from facultative pond was pumped out and after twoweeks of drying, the sludge depth was measured at differnt points in thepond and sludge samples were collected from three different section, i.e.10 m, 60 m 95 m and 115 m along the pond, and analysed for totalphosphorous, total kjeldahl nitrogen and volatile solid content insludge.

3.4 Analytical Method

All parameters mentioned above, except TP and TKN analysis in sludge,were analysed according to Standard Methods for Water and Wastewater(APHA, AWWA and WPCF, 1985). Total phosphorous and total kjeldahl nitrogencontent of sludge were measured by AOAC (1985) and EPA (1973) methodrespectively. For wastewater, all the parameters were analysed unfilter.The detail of methods adopted for wastewater and sludge analysis are givenin Table 3.1.

-20-

Table 3.1 Parameters and Analysis Method.

Parameters

Wastewater

B 0 D5NH3-N

Org-NTKNTPDetergent

Sludge

TPTKNVolatile solid

Method of analysis

Incubation at 20°C for 5-days

Titrimetric method

Macro-kjeldahl methodMacro-kjeldahl methodStannous chloride methodMéthylène blue method

Molybdovanadophosphate method (AOAC)Macro-kjeldahl method (EPA)Igniting at 550°C for one hour

K-

Influent <fT

(SI

f

-50 m

ANA€R0BIC [ Q-POND

Illl

A Lï\

ITT

/III

ANAEROBICPOND

I I I

/

SOr

L

PLAN

o

SECTION A - A

Rg. 3.1 Layout of AIT Waste Stabilization Pond

Inflow^WOODEN „FOOT PATH

WATERHYACINTH

POND

11111H10 30 60

Rg.3.2 : Sampling points Location in Facultative Pond and Water Hyacinth Pond

Hi ,

FIOH10

F30.H30» "60H He

Sampling points in facultative pondSampling points in water hyacinth pond

Inflow : Anaerobic pond influent

-23-

IV RESULTS AND DISCUSSION

4.1 Results

The detail data of the first and second stage experimental works aretabulated and shown in Appendix A and B sections. The averageconcentration value of each parameter at different points for first andsecond stage are given in Table 4.1 and 4.2, and their percent reductionare correspondingly presented in Table 4.3 and 4.4 respectively. Thevariation of effluent concentration with observation time and theirreduction along the pond for both systems during both stages are presentedgraphically from Fig. 4.1 to 4.6 and 4.8 to 4.18 respectively.

The water hyacinth pond, after two years of operation without anymaintenance like regular harvesting, did not show better treatmentefficiency for total phosphorous and ammonia nitrogen , as compared tofacultative pond in treating the domestic wastewater from AIT campus.However, organic, nitrite and nitrate nitrogen removal was. comparativelybetter in water hyacinth ponds. On increasing the volumetric loading inwater hyacinth pond the efficiency further decreased for all parameters,but their effluent concentration value were well within the limit. In thebeginning of first stage, the water hyacinth pond effluent color wasslightly yellowish but it turned to blackish at the end of second stageexperiment. The dissolved oxygen concentration in facultative pond wasmuch higher than water hyacinth pond. The mean effluent DO concentrationin water hyacinth pond during first and second stage were 0.4 tng/L and0.26 mg/L respectively compared to last year measured value of 0.9 mg/L(SAPKOTA, 1987). Odor was observed at the effluent weir of the waterhyacinth pond which may be due to evolution of hydrogen sulfide gas fromsediment. A large quantity of foam was produced in hyacinth pond effluentchamber during both stages, but it was never seen in facultative pond.

4.2 Discussion

On the basis of experimental data, a brief discussion about all themeasured parameters for facultative and water hyacinth pond during bothstages are presented in the following section.

4.2.1 Total Nitrogen

The average total kjeldahl nitrogen (TKN), ammonia nitrogen (NHg-N),

organic nitrogen (ORG-N), nitrite nitrogen (NO,-N) and nitrate nitrogen

(NO.-N) concentration at different points in facultative and water

hyacinth pond during first stage are given in Table 4.1. Total kjeldahlnitrogen was reduced in both systems with almost same rate. The mean TKNeffluent concentration for facultative pond and water hyacinth pond were9.03 mg/L and 9.20 mg/L respectively. At distance of 10 m, in facultativeand hyacinth pond the concentration suddenly dropped from influentconcentration of 14.40 mg/L to 9.56 mg/L and 14.38 mg/L to 11.65 mg/Lrespectively. The fluctuation of TKN concentration in facultative pondwere comparatively higher than hyacinth pond. Table 4.2 shows the TKNconcentration at differnt points in hyacinth pond during second stage.

Table 4.1 Average Wastewater Characteristics for Dif ferent Points in Facultative Pond and Water Hyacinth Pond DuringFfrst and Second Stage Experiment

Pa rameters

MHo-N mg/L

Org-N mg/L

NO2-N mg/L

NOa-N mg/L

TKN mg/L

TP * mg/L

DO mg/L

PH

Temperature °C

Flow Rate, m3/d

Detention Time(days)

Fi

10. t|8

3.83

0.009

0.077

1lt.H0

2.27

2. 12

7.70

30.70

483.30

Facultat

F10

5.91

3.40

o.im

0.095

9.56

2.06

10.75

8. tO

30.70

;ive Pond

F30

5.89

3.05

0.160

0.102

9.19

1.96

12.09

8.50

30.80

13

F60

5.90

3.11

0.130

0.096

9.23

1.95

12.07

6.50

30.80

Fe

6.20

2.84

0. 177

0.119

9.03

1.93

8.52

8.40

30.50

385.24

Water Hyacinth Pond

Hi

10.76

3.64

0.014

0.115

1U.38

2.23

1 . 18

7.60

30.80

465.77

H10

9.12

2.46

0.010

0.079

11.65

2.14

0.59

7.30

28.50

H30

8.32

1.83

0.008

0.079

10.41

2.05

o.n9

7.30

28.00

13

H60

7.93

1.55

0.00

0.06

9.74

2.04

0.50

7.20

27.80

He

7.57

1.27

0.012

0.069

9.20

2.02

0.40

7.20

27.30

387.49

to•F-i

-25-

The average influent and effluent concentration were 15.67 mg/L and 11.15mg/L respectively. However, the TKN concentration measured during secondstage were higher than first stage value at any point in the system. Fig.4.1 shows the variation of the effluent TKN concentration at differentday of observations in facultative and hyacinth pond for both stages. TheTKN value at the beginning of first stage was lower, but it increased withfunction of time during the entire experiment period.

Table 4.2 Average Wastewater Characteristics for DifferentWater Hyacinth Pond During Second Stage.

Points in

Parameters

NO -N mg/LNO -N mg/LTKN mg/LTP mg/LDO mg/LpHTemperature °CFlow Rate m3/dDetention Time

(day)

Hi

0.0140.05915.072.250.227.46

29.27839.32

H10

0.0130.0513.242.180.457.36

26.89

H30

0.0130.05312.262.110.397.35

26.28

6

H60

0.0120.05011.742.090.367.31

25.94

He

0.0180.0511.152.070.267.23

25.59579.09

Ammonia nitrogen reduction in facultative pond was comparativelyhigher than hyacinth pond. The mean effluent concentration forfacultative pond and water hyacinth pond were 6.02 mg/L and 7.57 mg/Lrespectively. It was interesting to note that in case of facultative pondthe concentration drop at 10 m was so low that the value was even lowerthan average effluent concentration. Minimum average concentration infacultative pond system was observed to be 5.89 mg/L at 30 m distance.Higher ammonia removal in facultative pond than hyacinth pond may be dueto NH3 volatilization at high pH value and emperature. It has beenobserved during the experimental period that effluent ammoniaconcentration in hyacinth pond increases over as the time passes. Theeffluent concentrations at different days of observation are shown in Fig.4.2. Organic nitrogen reduction in hyacinth pond were comparativelyhigher than facultative pond. Mean effluent concentration for facultativepond and water hyacinth pond were 2.84 mg/L and 1.27 mg/L respectively.The effluent organic nitrogen concentrations at different days ofexperiment are shown in Fig. 4.3.

Nitrite and nitrate nitrogen reduction in water hyacinth pond wasmuch better than facultative pond. In facultative pond, the effluentconcentrations of nitrite and nitrate nitrogen were significantly higherthan influent value. The average effluent nitrite concentration forfacultative and water hyacinth pond in first stage were 0.177 mg/L and0.012 mg/L respectively. In second stage the effluent nitriteconcentration of water hyacinth pond increased to an average value of0.018 mg/L. The variation of effluent nitrite concentration at different

-26-

I

UJ

l U

1 *

1 3

1 2

11

1 0

9

S

7

6

-

-

-

-

-

-

-

1- 1

11

î

/

4.4.

flJ

2056

rJ

kg/(kg/(

•S

ha .ha .

B

d ) - FP Ud ) - HP*I

^ Av

• — 28. 60 kg/< ha. d ) -

i

^> f\ AY J

HP •

a Focultotlve pond •

+ Hyacinth pond

15—Oct OS-Nov 26-Nov 18-Dec O4—Jan

Dale of Experiment

25—Jan 19-Feb

Fig. 4. 1 Variation of Effluent TKN Concentration

E

IcQ

UJ

1O -

S -

7 -

o Facultotfve pond

••• Hyacinth pond

15—Oet 26—Oct 05— Nov 14—Nov

Dote of Experiment

26-Nov

Fig. 4.2 Variation of Effluent NH3-N Concentration

- 2 7 -

m

• Facultative pond

+ Hyacinth pond

O.615—Oet 26—Oct O5—Nov

Date of Experiment

—Nov 26-Nov

Fig. 4. 3 Variation of Effluent Org-N Concentration

0. 026 kg/( ha. d>~ HP0. 0088 kg/( ha. d)0. 014 kg/( ha. d)

Facultativo pond

+ Hyacinth pond

19-Feb

Date of Experiment

Fig. 4.4 Variation of Effluent NO2 Concentration

- 2 8 -

0. 108 kg/< ha . d ) - HP

o»

cu

eu

I

o Facultative pond

+ Hyocînth pond

Fig. 4. 5 Variation of Effluent N03 Concentration

2.B

cV

i.

a Facultative pond

+ Hyacinth pond

. 23 kg/( ha. d) — 4; 10 kg/( ha. d)2. 26 kq/( ha. d)

IS—Oct OS—Nov 26 — Nov 1fl-Oec O*—Jan

Dote of Experiment

25-Jon 19-Feb

Fig. 4.6 Variation of Effluent TP Concentration

-29-

day of observations for both ponds and both stages are shown in Fig. 4.4.The average effluent nitrate nitrogen concentration of facultative andwater hyacinth pond during first stage were 0.119 mg/L and 0.069 mg/Lrespectively. During second stage the effluent nitrate nitrogenconcentration decreased to an average value of 0.05 mg/L. Theconcentration of effluent nitrate at different days of experiment areshown in Fig. 4.5. During first stage, the mean effluent total nitrogen(organic + inorganic) concentration was having the lower value of 9.281mg/L in water hyacinth as compared to 9.326 mg/L value in facultativepond. On increasing the load in water hyacinth pond, the effluent valueincreased to 11.218 mg/L (Fig. 4.17).

4.2.2 Total Phosphorous

During first stage, the reduction of total phosphorous (TP) in bothponds was insignificant. The TP effluent concentration of facultativepond and water hyacinth pond have little consistent. Mean TP concentrationat different points in the both systems are given in Table 4.1. Theaverage effluent concentration for facultative pond and water hyacinthpond were 1.93 mg/L and 2.02 mg/L respectively. TP removal wascomparatively better in facultative pond than hyacinth pond system. Themean TP concentration at different points in water hyacinth pond duringsecond stage are given in table 4.2. The average effluent TP concentrationin water hyacinth pond for first stage was 2.02 mg/L compared to 2.07 mg/Lvalue in second stage. However the increase in TP concentration duringdouble loading was insignificant. The variation of effluent TPconcentration at different days of observation, in facultative andhyacinth pond for both stages are shown in Fig. 4.6.

As shown in figure, the concentration of total phosphorous increasedas time passed. Low TP concentration at the begining of the first stagewas due to new water hyacinth planted in the water hyacinth pond whereasat the start of second stage it was due to introduction of new waterhyacinth plant in the anaerobic pond. During second stage TP concentrationincreased further which might be due to release , of phosphorous towastewater at low DO concentration.

4.3 Statistical Analysis of the Data

The measured parameters in facultative and water hyacinth pondshowed a wide range of fluctuation. Therefore to describe the fluctuationof parameters, the influent and effluent concentration data were testedfor normal distribution by statistical software (Statpro) and log normaldistribution on log normal probability paper. Eventhough the data werenormally distributed, the log-normal gave the better result and thereforeto define the fluctuation of parameters, the influent and effluentconcentration of all parameters for both systems and both stages wereplotted on log-normal probability paper and presented in Fig. 4.7 (a)to 4.7 (j). The percent occurance of the data at any particularconcentration, or vice versa, can be find out directely from these graphs.

- 3 0 -

100

50

30

.20

i»I8u 6

54

L¿-

'

ifl

EffI

i«nt

utnt

F

^ =ÉJn

5 10 20 30405060 70 80 90 95Cumulative Frequency in %

( a ) TKN ( I st stage )

100!

50

30

*—- - — —'H

• • "

^ *

- —

nfl

•ffl

-—•

ueni

iMnl|

—--

—

—

5 10 20 304050 6070 80 90 95CumuloHve Frequency in %

( b ) TKN ( 2 nd stage )

100

50

30

f20

s 1 0

7654

&2 ^ -

ai _;_

F-^^^

F " * *

* - -

^ =

v—

IrtfEff lu«r

H

*

t *

—

5 »0 20 3040506070 80 90 95Cumulative , Frequency in %

( c ) NH3 - N ( I st stage )

10

765

4

3

oIIoJ 0.7

0.50.4Q3

Q2

0.1

•*—1

- t '

,íH-

=!

--

ínfl

Eff

Eí

C

C

1

_ s s J

/

*>"

1 —í —

, - — •

["10 20 304050 6070 60 90 95

Cumulative Frequency in %

(d ) Org - N ( I st stage )

- 3 1 -

0.»,

0.05

0.03

^ 0 . 0 2

co

i 0.008

.005

.003

.001

H

¿d

InfluentEffluent

I I I5 10 20 3040506070 80 90 95


(e ) NCfe-N (Iststoge)

O.K)

.08

.06

0.04

0.03

g1 0.02

Ii .0

1.005

.003

.002

.001

Influent - - - -Effluent —

I I I 15 10 20 3040506070 80 90 95


( f ) N02-N (2nd stage)

0.8

as

0.4

0.3

r 0.2

cSÕë aiw

3 0.07

aos

0.03

ao2

0.01

>

<

/

s

y

yyV

i

E

|

/

nfli:tti

1

*

lentuent

i

H\ /

/ "

<<

/

.....

*•


( g ) NO3-N (1st stage)

0.8

0.6

0.4

_i

r 0.2

c.2oÏ 0.1«iu

<s ° 0 7

0.05

0 0 3

0.02

0015 10 2<1 1

H

\

1(

|

nfh:fff

|

jenluent

|1 A

11 OK

Cumulative Frequency' in % ,

( h ) N03-N ( 2 n d stage)

-32-

57654

3

t«g

lig 7O g

.54

.3

.2

1

.—-

----/H

—sa

l i

E

ss•i

fitfflt

enttent

F/

F

Í1 ,§ 9

U .6.5

.4

.3

10 20 3040506070 80 90 95Cumulative Frequency in %

( i ) TP ( 1st stage)

1 - -_ — - -

nfliEffl

j«n

Ht -t -

— -

H *


( j ) TP (2nd stage)

Fig.4.7 : Cumulative Frequency of influent and Effluent Concen-tration ( F= Facultative pond , H = Hyacinth pond )

-33-

4.4 Removal Efficiency

The removal efficiency for facultative pond and the water hyacinthpond, calculated on concentration basis for first and second stage aregiven in Table 4.3 and 4.4 respectively. Eventhough the water hyacinthwas not harvested regularly the removal efficiency for the water hyacinthpond was much better than facultative pond in removing organic nitrogen,nitrite nitrogen and nitrate nitrogen. Other parameters like; TKN,ammonia nitrogen and total phosphorous removal was not better as comparedto the facultative pond. During second stage, when the load was doubled,the removal efficiency for water hyacinth pond decreased considerably forall parameters, due to increase of hydraulic and organic loading andsubsequently decrease of detention time. In both stages, the averagepercent removal for all measured parameters, except nitrite and nitratenitrogen, was more than 50 % at 10 m distance in both facultative andwater hyacinth pond. Table 4.3 and 4.4, and Fig. 4.8 to 4.13 shows thereduction of concentration for different parameters at different pointsalong the facultative and water hyacinth pond for both stages.

The removal efficiency for facultative and water hyacinth pond onaverage mass flux basis has also been calculated for first and secondstage and given in Table 4.5. The calculation is based on the averageconcentration and average flow rate, since the flow rate fluctuation inponds was insignificant.

Average percent removal of total kjeldahl nitrogen, ammonianitrogen, organic nitrogen, nitrite nitrogen and nitrate nitrogen atdifferent points in facultative pond and hyacinth pond for first andsecond stage are given in Table 4.3 and 4.4 respectively and theirconcentration reduction are graphically presented in Fig. 4.8 to 4.12.During first stage, total kjeldahl nitrogen reduction for both systemswas almost same, with slightly higher removal rate in facultative pond.The average TKN percent removal in facultative pond and water hyacinthpond were 37 % and 36 % respectively. TKN removal at 10 m distance infacultative and water hyacinth pond were about 90 % and 52 % respectively,of total TKN removal in corresponding pond system. The maximum rate ofreduction at 10 m may be due to settling of settleable fraction of theTKN and presence of its high concentration near the inlet zone. The reasonfor maximum removal of TKN in facultative pond compared to hyacinth pond,may be due to high ammonia removal (which is main constituent of TKN) infacultative pond at suitable condition. The TKN reduction in waterhyacinth decreased from 36 % in first stage to 26 % in second stage. Thedecrease in TKN reduction during second stage might be due to loadincrease and subsequently decrease in detention time (CORNWELL et al.,1977). The comparatively low DO concentration during second stage mightbe also one of the reason for decrease in nitrogen reduction. Fig 4.8shows the average TKN reduction at different points in facultative andhyacinth pond for both stages.

-34-

Table 4.3 Removal Efficiency (%) at Different Points in Facultative andWater Hyacinth Pond During First Stage Experiment.

1

| Sampling points

11 Fi| FIO| F30

F60Fe

1 HiH10H30H60He

NH3-N

044444443

015232630

Org-N

0U201926

032505765

NO2-N

0-1167-1678-1344-1867

0294350,14

N03-N

0-23-31-25-55

031314540

TKN

034363637

019283236

I 1TP

09 1141415

o i4 1899

Table 4.4 Removal Efficiency (%) at Different Points in Water HyacinthPond During Second Stage Experiment.

Sampling Points

1

1HiH10H30H60He

N02-N

07714-29

NO3-N

015101515

TKN

o12192226

TP

0367

-35-

Table 4.5 Removal of NH3"N, Org-N, NO^N, NO3~N, TKN and TP in

Facultative Pond and Water Hyacinth Pond for First and SecondStage.

Parameters

NH -NOrg-NNO -NNO -NTKNTP

First

Facultative Pond

kg/(ha.d)

5.611.55

-0.08-0.027.100.73

%

5441

-935-245033

Stage

Hyacinth

kg/(ha.d)

4.522.620.0040.0586.810.56

Pond

%

417129504725

kg/

00141

Second

Hyacinth

(ha.d)|

__--.003.045 |.564.47

Stage

Pond

%

«.---12425136

The average ammonia nitrogen removal in facultative pond was alwayshigher than water hyacinth pond during the entire experiment period.Ammonia reduction in facultive pond was 43 % compared to 30 % in waterhyacinth pond. However, it is believed that the main ammonia removalmachanism like; ammonia volatilization, gaseous ammonis stripping to theatmosphere and nitrification are strongly dependent on pH value,temperature and dissolved oxygen of the wastewater (STOWELL et al., 1981,HAUSER, 1984 and SHAMMAS, 1986). According to WILD et al., (1971) andEDELINE and LAMBERT (1974), the dissolved oxygen concentration of thewastewater must be above 0.60-1.0 mg/L for bacterial nitrification. Theoptimum pH value and temperature for maximum rate of nitrification are8.40 and 30°C respectively (WILD et al., 1971). This hypothesis isconfirmed in case of facultative pond, when ammonia nitrogen removal wasmaximum at 10 m in the pond where pH value, temperature and DOconcentration measured were favorable for nitrification. The sudden highreduction of ammonia near inlet zone is expected due to abrupt change ofabove mentioned affecting factors as well as the settling of settleablefraction of ammonia. Average ammonia nitrogen reduction at 10 m distancein facultative pond was 102 % of total reduction of pond system comparedto 51 % in water hyacinth pond. Organic nitrogen removal in facultativepond and water hyacinth pond were 26 % and 65 % respectively. High organicnitrogen reduction in water hyacinth pond may be due to suitable conditionfor conversion of organic nitrogen to ammonia nitrogen by the action ofsaprophytic bacteria. Like other parameters, a marked reduction inorganic nitrogen also occured at a distance of 10 m in both ponds. Fig.4.9 and 4.10 show the average ammonia and organic nitrogen reduction atdifferent points respectively.

The removal efficiency of water hyacinth pond in removing nitriteand nitrate nitrogen was always greater than facultative pond. Duringfirst stage the average percent removal of nitrite nitrogen in water

-36-

!Eu

s

fI

a Facultative pond 1 at stage

+ Hyacinth pond 1st «tago

* Hyacinth pond 2nd stage

S O TOO

Distance (m)

Fig. 4. 8 TKN Reduction along the Ponds

« O S O 1OO

1ZO

1 2 O

Distance

Fig. 4. 9 Ammonia Reduction along the Ponds

-37-

u

I•Io

5 -

4. -

3 -

2 -

Q Facultative pond

•t Hyacinth pond

4O 8ODistance (m)

eo 1OO 120

Fig. 4.10 ORG-N Reduction along the Ponds

I• Facultative pond 1 at stage

•* Hyacinth pond 1st stage

Hyacinth pond 2nd stage

2 O 4O SODistance (m)

BO—i

1OO 12O

Fig. 4.11 Nitrite Reduction along the Ponds

-38-

hyacinth pond and facultative pond were 14 % and -1867 % respectively,but in second stage the removal efficiency decreased from 14 % to -29 %in water hyacinth pond. The average nitrite concentration at differentpoints in both systems for both stages are shown in Fig. 4.11. Percentremoval of nitrate nitrogen in water hyacinth pond was 40 % as compareto -54 % in facultative pond during first stage. However, in second stagethe nitrate nitrogen removal efficiency of water hyacinth pond decreasedto 15 %. The average nitrate concentration at different points infacultative pond and water hyacinth pond, along the systems, for bothstages are shown in Fig. 4.12.

Nitrification and denitrification play a important role inincreasing the nitrite and nitrate nitrogen concentration in facultativepond and their reduction in water hyacinth pond respectively. As alreadydiscussed in ammonia nitrogen removal mechanism, the facultative pondprovides the suitable condition for nitrification process, and so theincrease in nitrite and nitrate nitrogen concentration in facultativepond is justified. However, the reduction of nitrite and nitrate nitrogenin water hyacinth pond is the result of denitrification process.

In facultative pond, the nitrite and nitrate nitrogen concentrationincreased but amount present was insignificant compared to ammonia andorganic nitrogen, hence increase in their concentration in facultativepond and decrease in hyacinth pond makes hardly any difference in totalnitrogen concentration in the ponds. Fig. 4.13 and 4.14 shows thedifferent forms of nitrogen present in facultative and water hyacinth pondrespectively. Nitrite and nitrate nitrogen concentration in both ponds,as shown in graphs, are insignificant compare to ammonia and organicnitrogen. The trend of nitrite and nitrate nitrogen concentration changein facultative and water hyacinth pond during first and second stage areshown in Fig. 4.15 and 4.16 respectively. However the percent removal oftotal nitrogen in facultative and water hyacinth pond was equal with valueof 36 %. During second stage, percent removal of total nitrogen in waterhyacinth decreased to 26 %. Mean total nitrogen concentration at differentpoints in facultative and water hyacinth pond during both stages are shownin Fig. 4.17.

The total phosphorous removal in facultative and hyacinth pond wasnot effective in either stage. TP reduction at different points infacultative and hyacinth pond during first stage are given in Table 4-3.The average TP removal in facultative pond and hyacinth pond were 15 %and 9 % respectively. The maximum TP reduction occured only upto 30 mdistance in both systems, and the reason for this maximum removal isexpected due to the occurance of physical, chemical and biological processat maximum rate near the entrance zone of facultative and hyacinth pond.In case of water hyacinth system, it is necessary to harvest the plantregularly to keep the phosphorous reduction rate maximum (WOLVERTON andMcDONALD, 1975). After continuous operation of the same system for 25 to30 days, the phosphorous removal efficiency declined upto 5 to 8 percent(CHEREMISINOFF, 1987). Data obtained from this experiment justify theirstatements.

The phosphorous removal decreased from 9 % in first stage to 8 % insecond stage. The average percent reduction of TP at different points in

-39-

O-12

0.11 -

O.O5 -

O.O4.

O Facultative pond 1 at stage

4 Hyacinth pond 1st stage

<* Hyacinth pond 2nd atage

6O

Distance (m)

1OO 12O

Fig. 4.12 Nitrate Reduction along the Ponds

-40-

u

• Ammonia Nitrogen

••* Organic Nitrogen

o Nitrito Nitrogen

A Nitrate Nitrogen

2.O 4O SO

Distance (m)

SO 1OO 12O

Fig. 4.13 Different forms of Nitrogen in Facultative Pond

11

1O -

9 -

8 -

7 -

6 -

5 -

A- -

3 -

2. -

1 -

O •*

a Ammonia Nitrogen

+ Organic Nitrogen

* Nitrite Nitrogen

a. Nitrate Nitrogen

2 O AO CO

Distance ( m )

8O TOO 12O

Fig. 4.14 Different forms of Nitrogen in Hater Hyacinth Pond

-41-

o.ia

• Nitrite In facultative pond

+• Nitrato in facultativo pond

Nitrite in hyacinth pond

A Nitrato in hyacinth pond

2 O 4O BO

Distance (m)

SO 1OO 12O

Fig. 4.15 NO2-N and NO3-N in Facultative and HaterHyacinth Pond

O.12

• Nitrite Tn first ata go

•+• Nitrate In first stage

O Nitrite in second stage

A Nitrate In second stage

2 O -*O 6O

Distance (n

8 O 1OO 12O

Fig. 4.16 NO2-N and NO3-N in Water Hyacinth Pond

-42-

ti

íÜ-3a

O Facultative pond 1st stage

-f Hyacinth pond 1st stage

<• Hyacinth pond 2nd stage

11 -

1O -

2O AÙ BO

Distance (m)

TOO 12O

Fig. 4.17 Total Nitrogen Reduction along the Ponds

o»É

-P

So

So

2.4 -

2.3 -

2.2 -

2.1 -

2 -

1.9 -

1.S -

O Facultative pond 1st stage

+ Hyacinth pond 1st stage

« Hyacinth pond 2nd stage

Î

\Si>=—•' V^ ̂ *— .

\ _ _ _ _ _ ,. 1

4O 6O

Distance (m)

« O TOO 12O

Fig. 4.18 TP Reduction along the Ponds

-43-

water hyacinth pond during second stage are given In Table 4.4 and theirconcentration along the pond are shown in Fig. 4.18. However, one of thereason for low TP reduction either in first or second stage may be dueto low DO concentration, which make the system anaerobic in which casephosphorous is released instead of removed.

4.5 Dissolved Oxygen, pH and Temperature

The measured value of dissolved oxygen, pH and temperature atdifferent points in facultative pond and water hyacinth pond during bothstages are given in Table 4.1 and 4.2. DO concentration increased infacultative pond from influent average 2.12 mg/L to effluent average 8.52mg/L. A maximum value of 28.60 rog/L was observed in facultative pond at30 m distance at 1.45 PM. After calculating the average value for entireexperiment period, corresponding to observation time and distance, themaximum value of 24.48 mg/L and 12.09 mg/L was observed at 3.00 PM and30 m distance respectively. From the observed value it can be concludedthat the photosynthesis rate, which is the main source of oxygenproduction in facultative pond is maximum at the middle of the pond andat around 3.00 PM. Fig. 4.19 shows the diurnal variation of dissolvedoxygen at different points in facultative pond whereas its diurnalvariation in complete pond system (calculated on average basis) is shownin Fig. 4.20. As shown in these figures the dissolved oxygen in thesystem were maximum all the time at 30 and 60 m and at 3.00 PM.

In water hyacinth pond, during first stage, dissolved oxygendecreased from an average value of 1.18 mg/L influent to 0.40 mg/Leffluent. The average dissolved oxygen in hyacinth pond system was lessthan 0.6 mg/L, decreasing from influent to effluent side. The reasonbehind this low DO in hyacinth pond were 1) firstly, the oxygen producedby water hyacinth during photosynthesis did not contribute to theoxidation process within the pond thus increasing the anaerobic portionof pond (Thomas & Phelp, 1987), 2) secondly, because of slow growth ofthe plant (after becoming the plants old), black color of the roots (dueto absorption of pollutants from wastewater) and persistence of hydrogensulfide produced check the oxygen transfer capacity of the hyacinth plant(Orth et al.. 1987).

During second stage, the average influent and effluent DOconcentration of water hyacinth pond were 0.22 mg/L and 0.26 mg/Lrespectively. The maximum DO concentration of 0.45 mg/L was measured at10 m distance. DO concentration at different points in facultative pondand water hyacinth pond for both stages are shown in Fig. 4.21.

The pH value fluctuation in both system was moderate. The influentand effluent pH value in facultative pond averaged 7.7 and 8.4respectively, with maximum average pH value of 8.5 at middle of pond,whereas in hyacinth pond the influent and effluent pH value averaged 7.6and 7.2 respectively. The increase in pH of 0.70 units in facultative pondwas due to the depletion of carbon di-oxide during algal photosynthesis,as confirmed by sporadic measurements, whereas the decrease of 0.40 pHunits in hyacinth pond was due to saturation of wastewater with carbondi-oxide produced in anaerobic condition which was obstructed to release

-44-

£

o-ouJzOn

ë

3O

28 -

26 -

2-4 -

22 -

2O -

lé -16 -

12 -

1O -

5 -

6 -

A -

2 -

OO 6

O Influant

+ At 1O m

* At 30 m

A At «O m

x Effluent

09:00 10:30

Time (hr)

1 2:3O 1-*:OO 17:OO

F i g . 4 . 1 9 Diurnal Variation of DO at Differnt Pointsin Facultative Pond

<E

X

O

O

në

7 AM 5 PM

Fig. 4.20 Diurnal Variation of DO in Facultative Pond

- 4 5 -

E

u

o"Dti

"5n

.B

• Facultative pond 1st stage

-f Hyacinth pond 1st stage

O Hyacinth pond 2nd stage

2 O— , —

4O

— 1 —

eo—,—so 1 0 0 1 2 0

Distance (m)

Fig. 4.21 DO Distribution in Ponds

e.e

o Facultative pond 1st stage

+ Hyacinth pond 1st stage

<> Hyacinth pond 2nd stage

2 O 4O 6O

Distance (m)

8 O 1OO 1 2 O

¡rt Fig. 4. 22 pH Value in Ponds

-46-

by a dense mat of water hyacinth to some extent. The pH in water hyacinthsystem was maintained around 7.3 units with the buffering capacity ofhyacinth. This buffering effect by water hyacinth was also observed inprevious studies (WOLVERTON & McDONALD, 1979, and McDoNALD & WOLVERTON,1980). During second stage, the average influent pH value decreased from7.60 units of first stage to 7.50. The decrease of pH in second stage maybe due to introduction of water hyacinth in anaerobic pond. However thepH at other points in the system were higher than first stage, and thereason for this increment is not known. The average pH value at differentpoints in facultative and water hyacinth pond for both stages are givenin Table 4.2 and 4.2, and also shown in Fig. 4.22.

The average influent temperature of facultative and hyacinth pondswere 30.70'C and 30.80°C respectively. In facultative pond temperatureraised at 30 m and 60 m to the average value of 30.83°C and 30.800Crespectively and decreased slightly at effluent to an average value of30.50°C. The average effluent temperature in water hyacinth pond was27.30°C showing a temperature loss of 3.50°C in the pond. This effect wasperhaps due to shading and evaporating cooling. All measured value wereabove 22°C throughout the study period showing very favourable for waterhyacinth growth. A considerable decrease in temperature was observedduring load increase. The average temperature at different points infacultative pond and hyacinth pond during both stages are given in Table4.1 and 4.2, and presented graphically in Fig. 4.23.

4.6 Water Losses

By measuring the influent and effluent discharge of facultative pondand water hyacinth pond, the water loss through each system has beencalculated. The water loss of 20 % and 17 % was observed in facultativepond and water hyacinth pond respectively during first stage, and 31 %in water hyacinth pond during second stage. During second stage, thefacultative pond and anaerobic pond, parallel to water hyacinth sectionpresently on operation, were dry and seepage towards these empty pondswas noticed which caused the increase in water loss. Secondly the weather,which was dry and hot during second stage compared to seldom rain in firststage, might have effected the loss due to evaporation andevapotranspiration.

Loss of water in any treatment system has considerable effect on itseffluent concentration. Having the same pollutants content in effluent,the decrease in effluent flow will increase the concentration. Here insecond stage, the water loss in water hyacinth pond is Comparatively 14% higher than the first stage, so the effluent concentration in secondstage is expected 14 % less than first stage.

4.7 Sludge Accumulation and its Characteristics

In facultative pond, a certain amount of sludge accumulation hastaken place. Anaerobic decomposition gives a non-degradable residue whilethe original load of silt and inorganic solids entering the pond alongwith raw sewage also settles at the pond bottom.

-47-

D Facultative pond 1st stage

•+ Hyacinth pond 1st stage

* Hyacinth pond 2nd ata g o

AO &O

Dîstonce (m)ao 1OO 12O

Fig. 4.23 Temperature distribution in ponds

-48-

Depth of the sludge accumulated in facultative pond was measured atdifferent points, along and across the pond (Fig 4.24), after two weeksof pumping out the wastewater. The average depth of sludge in the systemwas found 22.15 cm, and during measuring time about 5.0 cm depth of sludgewas reduced, which was observed by fixing the three pegs at differntpoints along the pond. Hence the actual total average depth of sludgeaccumulated in facultative pond was 27.15 cm.

Sludge depth of 45 cm was measured near the inlet at the middle ofthe pond width and tapered down to about 15 cm near the outlet end. Asshown in Fig. 4.24, the sludge depth was also tapered down to about 10cm near the ends of the pond width. The total volume of the sludgeaccumulated during 15 years of pond operation and serving a populationof about 1200 people was found to be about 4563.0 m3 at rate of 0.069 m3

per person per year. This value is in the middle range of 0.05 and 0.08m3 per person per year as reported by GLOYNA (1971) and ARCEIVALA et al.(1970) respectively.

The fixed or inorganic solids contained in the sludge was found tobe about 15 percent whereas the volatile or organic fraction was about85 percent. The moisture content and dry density of the sludge wasmeasured about 85 % and 693 kg/m3 respectively. After two week of drying,the average total kjeldahl nitrogen (TKN) and total phosphorous (TP)contents in the accumulated sludge was found to be about 0.45 and 0.28 %respectively. Maximum nitrogen and phosphorous content in the sludge wasfound to be near the inlet and its values decreased toward the outlet ofthe pond.

4.8 Odor Release

A certain amount of hydrogen sulfide, which is most odorous gasesoften occurs in the domestic stabilization ponds, but when this isexcessive it may cause the malodor problem around the pond. Generallysulfide formation by bacterial reduction of sulfate contained inwastewater is limited to the anaerobic bottom layer of the pond, and ischemically or biochemically oxidized as it diffuses upward into theaerobic layers. But, if sulfide production is excessive and sufficientoxygen is not present on upper layer to oxidize the sulfide, odor problemresults.

During the entire period of experiment some odor was observed infacultative and hyacinth pond. In facultative pond, odor was felt onlyin the early morning, when DO concentration was very low in the upperlayer of the pond. In water hyacinth pond odor was recognised at theeffluent weir as DO concentration was always less than 0.5 mg/L makingupper layer anaerobic.

The reason behind the absence of malodor in facultative pond duringday time was the absence of hydrogen sulfide in the presence of sufficientDO in the upper layers and a pH value always higher than 8 in the pondsystem. The sufide formed in the anaerobic layers of the pond was oxidizedchemically or biochemically in the upper layers in presence of oxygen

- 4 9 -

1.5 4.5 4.5 4.5 4.5 4.5I m I m l m I m I m I m 4.5 4.5 , 4.5 ,1.5m I m I m |m|

# • • • •10 20 40 40 40 45 26 20 9

32

* •9 13 38 28 28 29 29 14 10

29

9 II 32 28 28 26 20 II 8

• 1220 18 14 15 10 18 20 20 28

at Imat 3m

— at 10m

— at 30m

~at60m

—at 80 m

-at 95 m

—at 110 m

—at 115 m

39 m

Fig.4.24 : Sludge Depth ¡n Facultative pond

(Average sludge depth = 22.15 cm)

-50-

which produced odorless product. Secondly at pH 8 or more, the most of

sulfide existed as odorless hydroaulfide ion (HS ) under conditions ofwhich the release of malodorous hydrogen sulfide gas was virtuallynon-existent (MARA, 1976). On the other hand, both the DO and pH valuewere comparatively lower in the water hyacinth pond which enhance theproduction of hydrogen sulfide (H2S) gas causing the malodor all the time.

The sulfide production in the pond is directly related with surfaceBOD loading, detention time and influent sulfate concentration (GLOYNAand ESPINO, 1968). When the load was doubled in hyacinth pond, BOD loadand sulfate concentration was increased and detention time was decreasedwhich caused the more sulfide and then hydrogen sulfide production insuitable condition resulting the strong malodor at that time.

4.9 Foaming in Water Hyacinth Pond

During the entire experiment period, a large quantity of foam wasproduced at effluent chamber of water hyacinth pond. Foam production wasnot so extensive in first stage, but during second stage it was extensivewith maximum height of about 2.0 meter at early morning and minimum heightof about 0.50 meter at rest of day. It has been concluded that foamingin effluent wastewater was due to presence of surplus amount of detergentin wastewater, but at the same time it was interesting to note that foamwas never seen in the effluent of facultative pond where same type ofwastewater was treated.

SAWYER (1958) reported that foaming in any treatment plant isdirectly related to the aeration of that wastewater. He also reportedthat although the amount of detergent removal by sedimentation is verysmall, when it accumulates in the small volume of settled sludge, theconcentration is increased by factor of 100-400 fold. WELLS and SCHERER(1952) reported that frothing in sewage is function of suspended solidpresent, froth formation is high at low suspended solid concentration andvice versa. According to the statements mentioned above, the expectedreasons for foaming in water hyacinth effluent may be as follows:

i) Suspended solid concentration in water hyacinth pond effluent wasmuch lower than facultative pond.

ii) On mixing of the pond water, the accumulated detergent in sludgewas released to wastewater and discharged with effluent

Detergent concentration in the influent and effluent of waterhyacinth pond was measured and found that detergent content in effluentwas higher than influent which may be due to release of detergentaccumulated in the sediment. The average influent and effluent detergentconcentration were 0.39 mg/L and 0.47 mg/L respectively.

-51-

V CONCLUSIONS

1 After two years operation of water hyacinth pond without anyregular maintenance, the efficiency of the system decreasedsignificantly in removing the nitrogen and phosphorous, but BOD5removal was not reduced proportionally. Nutrient removal,therefore is directly related to plants growth and theirharvesting rate, but BOD,, removal is not. Organic, nitrite and

nitrate nitrogen removal rate in water hyacinth system werecomparatively higher, but ammonia nitrogen and phosphorousremoval were lower than facultative pond. On increasing thevolumetric load in water hyacinth pond, the removal efficiencydecreased further for all parameters.

2 Dissolved oxygen concentration in facultative pond was muchhigher than water hyacinth pond. The effluent DO concentrationin water hyacinth pond was always lower than 0,5 mg/L. and thisvalue decreased further when load was increased.

3 In water hyacinth pond, foaming at effluent point and nuisancesmell from system, due to evolution of hydrogen sulfide gas, wasobserved throughout the experiment period.

4 During first stage, the percent removai for mean TKN, NH3-N,

Org-N, N02~N, NO» TP and BOD_ for facultative pond system were

37, 43, 26, -1867, -55, 15 and 67 % and for water hyacinth systemthe corresponding reduction were 36, 30, 65, 14, 40, 9, and 71 %respectively. When load increased in water hyacinth pond, thepercentage removal for NO2-N, NO3~N, TKN, TP and BOD. were -29,

15, 26, 8, and 66 % respectively.

5 Comparing the present study data with last year study, which wasconducted in the same pond by SAPKOTA (1987), it is concluded thatthe nutrient removal in water hyacinth pond decreases with time.To keep the nutrient reduction rate maximum, it is necessary toharvest the plant regularly and increase the DO concentration byaeration.

6 Water hyacinth is not effective for primary treatment ofwastewater. Although new water hyacinth plant was introduced inanaerobic pond during second stage, the removal efficiency systemwas poor compared to water hyacinth pond.

-52-

VI RECOMMENDATIONS FOR FUTURE STUDY

1 The experiment period should be increased at least for on yearto observe the effect of weather change on the treatmentefficiency of the system.

2 The effect of desludging on facultaive pond should beinvestigated to evaluate the operation of the pond systems andtheir maintenance.

3 Nutrients removal by water hyacinth plants, during their growthphase, is significantly high compared to other systems (ORTH andSAPKOTA, 1987). To keep the plants in growth phase, regularharvesting is essential which is most undesirable with economicalpoint of veiw. Hence the study should be conducted by restrictingthe plants only near the effluent side with regular harvesting,and the response of the system should be evaluated.

4 Harvesting frequency of the water hyacinth plant should beinvestigated for proper maintenance and operation of the systemand also the proper utilization of the plant in removing nitrogenand phosphorous from the wastewater.

-53-

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APHA, AWWA, and WPCF (1985), Standard Method for the Examination ofWater and Wastewater, 16th Edition, Washington D.C.

ARCEIVALA, S. J. (1981), Wastewater Treatment and Disposal: Engineeringand Ecology in Pollution Control, New York, Marcel dekker Inc.

ARCEIVALA, S. J., LAKSHMINARAYANA, J. S. S., ALAGARSAMY, S. R. andSASTRY, C. A. (1970), Waste Stabilisation Ponds Design,Construction and Operation in India, NEERI, Nagpur, India

ARTHUR, J. P. (1983), Notes on the Design and Operation of WasteStabilization Ponds in Warm Climates of Developing Countries, UrbanDevelopment Technical Papr Number 6, The World Bank Washington, D.C.

ASSENZO, J. R. and REID, G. W. (1966), Removing Nitrogen an Phosphorousby Bio-oxidation Ponds in Central Oklahoma, Water and Sewage Works,Vol. 113, No. 8, pp. 297-299.

BHAMIDIPATI, S. R. M. (1988), Removal of BOD, COD and Solids in aFacultative and a Water Hyacinth Pond: A Case Study, AIT, UnpublishedData.

BRANDLEY, R. M. (1983), BOD Removal Efficiencies in TwoStabilization Lagoons in Series in Malaysia, Water PollutionControl, Vol. 82, Part 1, pp. 114-122.

BOGAN, R. H., ALBERTSON, 0. E. and PLUNTZE, J. C. (1960), Us of Algaein Removing Phosphorous from Sewage, J. of Sanitary EngineeringDivision, ASCE, Vol. 86, No. SA5, pp. 1-20.

BUSH, A. F., ISHERWOOD, J. D. and RODGI, S. (1961), Dossolved SolidsRemoval from Wastewter by Algae, J. Sanitary EngineeringDivision, ASCE, Vol. 87, No. SA3 , pp. 39-57.

CANTER, L. W., ENGLANDE Jr., A. J. and MAULDIN Jr., A. F. (1969),Loading Rates on Waste Stab'ilization Ponds, J. of SanitaryEngineering Division, ASCE, Vol. 95, No. SA6, pp. 1117-1129.

CHEREMISINOFF, P. N. (1987), Biotechnology: Treating Industrialand Municipal Wastes and Wastewater, Pollution Engineering, Vol.XIX, No. 9, pp. 74-87.

CHIANG, W. W. and GLOYNA, E. F. (1970), Biodégradation in WasteStabilization Ponds. Center for Research in Water Resources ReportCRWR- 74, University of Texas, Austin, Texas.

-54-

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JOHNSON, W. K. (1968), Removal of Nitrogen by Biological Treatment,in Advance in water quality improvement, edited by Gloyna, E. F.and Eckenfelder Jr., W. W. , University of Texas Press, Austin &London, pp. 178-189.

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-57-

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-59-

APPENDIX - A

EXPERIMENTAL DATA DURING FIRST STAGE

LABORATORY ANALYSIS REPORT OF DIFFERENT PARAMETERSMEASURED FOR FACULTATIVE AND WATER HYACINTH PONDDURING FIRST STAGE

-60-

Table A.1 BOD During First Stage

Samp I ing

Date Time, hr

15-Oct 11:0017-0ct 13:0019-Oct 15:0022-0ct 06:4526-Oct 08:0030-Oct 08:3001-Nov 10:0003-Nov 12:0005-Nov 14:0008-Nov 09:0009-Nov 10:3011-Nov 15:4514-Nov 17:0018-Nov 09:4520-Nov 10:4523-Nov 13:4526-Nov 15:3030-Nov 13:3003-Dec 07:3006-Dec 09:3009-Oec 12:30

Average Value

Stand. Deviation

Maximum Va lue

Mini mum Va iue

Percent Removal

BOD (mg/L)

F i

46.0040.0042.0062.5045.0037.5030.0033.5031.0045.0030.0036.0032.1052.0037.0036.0040.0048.8049.6047.5042.40

41.14

8.10

62.50

30.00

FIO

24.0022.4024.0019.8016.8019.8021.6020.7021.5019.7017.8020.0019.8029.5022.2023.4024.0028.8018.0021.5020.30

21.70

3.12

29.50

16.80

47.26

F30

15.4018.5016.5023.4022.2015.6018.6017.6016.2017.5014.4019.5011.4018.5013.8027.0025.0022.5014.5014.0016.40

18.02

3.93

27.00

11 .40

56.19

F60

16.5521.0017.5020.0013.0017.5014.4015.2014.5013.0013.1019.5015.0017.1415.8623.1422.7022.2014.1414.5714.70

16.89

3.22

23.14

13.00

58.94

Fe

10.8020.5015.7511.1010.2010.0011.2013.8014.006.8010.2020.0012.4010.6012.6020.5020.5022.1010.1211.1012.80

13.67

4.33

22.10

6.80

66.77

Hi

47.5036.7540.0048.5042.5049.4043.7538.6038.7542.8037.5040.7535.0058.0042.2041.4037.5050.4033.0048.7045.60

42.79

5.89

58.00

33.00

H10

25.2029.0027.6028.0019.2031.2039.0020.4036.0027.6027.6025.2027.6026.4024.0027.6027.6022.2023.4015.6018.95

26.16

5.28

39.00

15,60

38.87

H3

23.5016.5016.0019.8013.8022.8017.5016.8021.6022.8023.4014.4021.6020.4023.4026.0024.0019.0021.0013.0015.80

19.67

3.71

26.00

13.00

54.03

H60

20.0019.5017.4018.5012.0016.5019.0012.5018.0019.5019.4013.2017.1420.5720.1424.4219.2915.0014.5712.0014.60

17.30

3.21

24.42

12.00

59.58

He

13.7513.5012.5012.9010.0011.4014.4010.6011.6014.5013.2012.6013.5014.1012.3013.5011.1014.4011.638.1011.50

12.43

1.60

14.50

8.10

70.95

Table A.I BOD During First Stage

-60-

Sampling

Date Time, hr

15-Oct 11:0017-Oct 13:0019-Oct 15:0022-0ct 06:1526-Oct 08:0030-Oct 08:3001-NDV 10:0003-Nov 12:0005-Nov 11:0008-Nov 09:0009-Nov 10:3011-Hov 15:1511-Nov 17:0018-Nov 09:1520-Nov 10:1523-Nov 13:1526-Nov 15:3030-Nov 13:3003-Dec 07:3006-Dec 09:3009-Dec 12:30

Average Value

Stand. Deviation

Maximum Va lue

Minimum Va 1ue

Percent Removal

BOD <mg/L)

F i

16.0010.0012.0062.5015.0037.5030.0033.5031 .0015.0030.0036.0032.1052.0037.0036.0010.0018.8019.6017.5042.10

11.11

8. 10

62.50

30.00

no21.0022.4021.0019.8016.8019.8021.6020.7021-5019.7017.8020.0019.8029.5022.2023.1021.0028.8018.0021.5020.30

21.70

3.12

29.50

16.80

17.26

F30

15.1018.5016.5023.1022.2015.6016.6017.6016.2017.5011.1019.5011.4018.5013.8027.0025.0022.5011.5011.0016.40

18.02

3.93

27.00

11.10

56.19

F60

16.5521.0017.5020.0013.0017.5011.1015.2011.5013.0013.1019-5015.0017.1115.8623.1122.7022.2011.1111.5711.70

16.89

3.22

23.11

13.00

58.94

Fe

10.8020.5015.7511.1010.2010.0011.2013.8014.006.8010.2020.0012.1010.6012.6020.5020.5022. 1010.1211.1012.80

13.67

1.33

22.10

6.80

66.77

Ht

47.5036.7540.0048.5042.5049.4013.7538.6038.7512.8037.5040.7535.0058.0042.2041.4037.5050.4033.0048.7045.60

42.79

5.89

58.00

33.00

mo25.2029.0037.6028.0019.2031.2039.0020.1036.0027.6027.6025.2027.6026.4024.0027.6027.6022.2023.4015.6018.95

26.16

5.28

39.00

15.60

38.87

H3

23.5016.5016.0019.8013.8022.8017.5016.8021.6022.8023.4014.4021.6020.4023.1026.0021.0019.0021.0013.0015.80

19.67

3.71

26.00

13.00

54.03

H60

20.0019.5017.4018.5012.0016.5019.0012.5018.0019.5019.4013.2017.1420.5720.1424.4219.2915.0014.5712.0014.60

17.30

3.21

24.42

12.00

59.58

He

13.7513.5012.5012.9010.0011.4014.4010.6011.6014.5013.2012.6013.5014.1012.3013.5011.1014.4011.638.1011.50

12.43

1.60

14.50

8.10

70.95

- 6 1 -

Tab le A .2 Ammonia N i t r o g e n During F i r s t Stage

Samp I Ing

Date Time, hr

15-0ct 11:0017-Oct 13:0019-Oct 15:0022-0ct 06:4526-Oct 08:0030-Oct 08:3001-Nov 10:0003-Nov 12:0005-Nov 14:0008-Nov 09:0009-Nov 10:3011-Nov 15:4514-Nov 17:0018-Nov 09:4520-Nov 10:4523-Nov 13:4526-Nov 15:3030-Nov 07:30

Average Va 1ue

Stand. Deviation

Maximum Va lue

Mini mum Va 1ue

Percent Remova 1

FI

11.768.5710.1113.9710.9211.739.886.749.1810.2211.1110.089.6311.4810.7011.499.6911.31

10.48

1.49

13.97

6.74

FIO

5.544.004.346.757.456.645.885.324.826.726.756.165.776.335.946.065.106.78

5.91

0.90

7.45

4.00

3.61

F30

5.244.234.656.806.786.526.365.324.736.527.036.026.306.055.996.204.207.11

5.89

0.91

7.11

4.20

43.80

F60

5.294.404.316.557.006.586.225.384.796.616.615.525.946.166.136.285.387.06

5.90

0.81

7.06

4.31

43.70

NH3-N

Fe

5.104.515.326.616.896.226.195.385.016.556.616.106.696.196.227.214.936.72

6.02

0.76

7.21

4.51

42.56

(mg/L)

Hi

9.589.639.7712.3511.1712.9410.508.2910.3610.6711. 1711. 1210.5011.0611.5912.029.3511.54

10.76

1.12

12.94

8.29

H10

8.688.067.819.358.349.418.517.398.408.659.2110.539.359.6610.2810.739.1810.64

9.12

0.96

10.73

7.39

15.24

H30

7.316.786.447.006.808.608.327.427.648.327.648.859.109.419.9410.639.1310.30

8.32

1.23

10.63

6.44

22.68

H60

6.276.616.386.106.668.067.536.977.007.907.598.328.909.169.4610.529.1010.14

7.93

1.33

10.52

6.10

26.30

He

5.826.165.946.476.616.527.117.066.757.367.368.018.608.468.7410.038.9510.30

7.57

1.31

10.30

5.82

29.65

-62-

Tabíe A,3 Organic Nitrogen During First Stage

Sampling

Date Time, hr

15-Oct 11:0017-Oct 13:0019-Oct 15:0022-Oct 06:4526-Oct 08:0030-Oct 08:3001-Nov 10:0003-Nov 12:0005-Nov 14:0008-Nov 09:0009-Nov 10:3011-Nov 15:4514-Nov 17:0016-Nov 09:4520-Nov 10:4523-Nov 13:4526-Nov 15:3030-Nov 07:30

Average Value

Stand. Deviation

Maximum Va lue

Mini mum Va Iue

Percent Removal

Fi

3.725.384.063.475.944.123.813.534.203.953.283.142.603.813.333.583.473.53

3.83

0.75

5.94

2.60

F10

2.183.394.794.983.193.443.283.563.082.582.322.463.812.463.393.464.034.76

3.40

0.82

4.98

2.18

11.23

F30

2.633.333.444.283.223.723.283.442.772.742.321.482.382.863.113.213.533.14

3.05

0.60

4.28

1.48

20.37

F60

2.633.423.503.673.023.443.753.613.502.662.162.462.352.833.223.303.283.25

3.11

0.47

3.75

2.16

18.80

Org-N

Fe

2.163.143.473.283.113.333.362.692.912.771.682.412.302.582.692.983.163.12

2.84

0.46

3.47

1.68

25.85

(mg/L)

Hi

3.584.593.953.923.003.723.953.534.202.943.163.583.284.423.583.723.193. 19

3.64

0.46

4.59

2.94

H10

2.742.742.863.532.072.602.552.552.492.301.932.412.662.162.242.341.962.13

2.46

0.37

3.53

1.93

32.42

H30

3.001.181.621.121.402.182.182.352.55

;

.32

.62

.71

.68

.68

.93Ï.07.79.57

1.83

0.47

3.00

1.12

49.73

H60

1.821.061.400.701.121.622.041.991.881.571.621.321.881.511.571.741.571.40

1.55

0.33

2.04

0.70

57.54

He

1.120.921.060.671.341.121.372.021.261.341.341.091.341.321.511.741.121.18

1.27

0.29

2.02

0.67

65.11

-63-

Table A.4 Nitr i te Nitrogen Our Ing F i rs t Stage

SamplIng

Date Time, hr

15-Oct 11:0017-Oct 13:0019-Oct 15:0022-Oct 06:1*526-Oct 08:0030-Oct 08:3001-Nov 10:0003-Nov 12:0005-Nov 14:0008-Nov 09:0009-Nov 10:3011-Nov 15:t»5114-Nov 17:0018-Nov 09:4520-Nov 10:4523-Nov 13:4526-Nov 15:3030-Nov 13:3003-Dec 07:3006-Dec 09:3009-Dec 12:30

N02-N (mg/L)

Fi

0.0160.0130.0120.0100.0070.0070.0100.0110.0060.0090.0100.0070.0130.0060.0100.0060.0070.0060.0120.0120.006

FIO

0.6780.49<*0.6890.0510.0080.0460.0280.0240.0380.0100.0900.0270.0400.0550.0130.0160.0280.0070.0080.0140.028

F30

0.9850.6751.0370.0510.0190.0530.0100.0250.0190.0090.0130.0450.05*40.1390.0140.0770.0350.0140.0090.0170.050

F60

0.9660.3230.4740.1180.0890.0890.0590.0520.0950.0220.0510.0700.0610.0460.0390.0330.0440.0250.0100.0150.040

Fe

1.1880.6810.6620.0990.0250.0740.0700.0700.0830.0250.0200.0600.0860.1700.0210.0760.0730.0730.0510.0200.083

HI

0.0060.0190.0310.0140.0120.0170.0070.0080.0100.0190.0160.0130.0130.0100.0130.0100.0160.0190.0150.0130.007

H1O

0.0060.0090.0230.0090.0100.0100.0080.0060.0070.0090.0120.0120.0110.0090.0100.0090.0140.0120.0080.0070.006

H3O

0.0190.0110.0220.0070.0090.0050.0060.0060.0050.0090.0090.0030.0040.0040.0090.0130.0120.0090.0030.0040.004

H60

0.0050.0070.0030.0060.0060.0030.0120.0060.0050.0070.0060.0050.0030.0030.0070.0110.0140.0150.0100.0080.008

He

0.0150.0380.0090.0070.0150.0060.0060.0050.0070.0160.0160.0130.0070.0070.0140.0170.0190.0190.0100.0080.004

Average Value 0.009 0.114 0.160 0.130 0.177 0.014 0.010 0.008 0.007 0.012

Stand. Deviation 0.003 0.-210 0.309 0.216 0.289 0.005 0.004 0.005 0.003 0.007

Maximum Value 0.016 0.689 1.037 0.966 1.188 0.031 0.023 0.022 0.015 0.038

Minimum Value 0.006 0.007 0.009 0.010 0.020 0.006 0.006 0.003 0.003 0.004

Percent Removal 1166.7 -1677.8 -1344.4 -1866.7 28.57 42.86 50.00 14.30

( Source: BHIMADIPATI, 1988 )

-64-

Table A.5 Ni t ra te Nitrogen During Fi rst Stage

Sampl

Date

15-Oct17-Oct19-Oct22-Oct26-Oct30-Oct01-Nov03-Nov05-Nov08-Nov09-Nov11-Nov14-Nov18-Nov20-Nov23-Nov26-Nov30-Nov03-Dec06-Dec09-Dec

Average

Stand. 1

Maximum

Mini mum

Percent

Ing

Time

11:13:15:06:08:08:10:

, hr

00000045003000

12:0014:09:10:15:

00003045

17:0009:10:13:15:13:07:09:12:

4545453030303030

Value

Deviation

Value

Va lue

Remova 1

0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.

0.

0.

0.

0,

Fi

120123090030030084120087030090060114066072054060096099060060063

077

029

123

030

FIO

0.1200. 1200.1500.1080.0330.1200.1200.1200.0900.0960.0330.0930.0900.0930.0360.0900. 1170.0870.0720.0900.114

0.095

0.030

0.150

0.033

0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.

0.

0.

0.

0.

-23.38 -32.

F30

150135180084054114132135066093093090063084090066096195039093087

102

039

195

039

F60

0.1440.1200.1350.0600.0300.1200.1200.1140.0330.0900.0480.1140.0750.1830.0480.0720.1170.1560.0660.0900.090

0.096

0.040

0.183

0.030

N03-N

Fe

0.1200.1200.1800.1050.0450.1050.1230.1350.0600.0900.1170.1140.0660.2160.1200.0960.1440.1170.2100.0930.126

0.119

0.042

0.216

0.045

47 -24.68 -54.55

(mg/L)

Hi

0.1500.8700.2340.0450.0270.0150.1050.0900.0600.0600.0540.0630.0600.1560.0480.0630.0870.0840.0360.0540.054

0.115

0.176

0.870

0.015

H10

0.0600.0900.3240.0750.0300.0600.1050.1020.0330.0600.0600.0660.0750.0930.0630.0540.0720.0600.0390.0690.075

0.079

0.058

0.324

0.030

H30

0.0840.0450.1890.0570.0450.0660.1350.1140.0240.0600.0750.0960.0630.0960.0720.0360.0870.0570.1470.0600.057

0.079

0.039

0.189

0.024

— 31.30 31.30

H60

0.0570.0600.0810.0330.0450.0600.1260.1170.0270.0600.0540.0600.0930.0720.0510.0330.0750.0540.0630.0570.051

0.063

0.024

0.126

0.027

He

0.0660.0360.1050.0360.0450.0600.1080.0870.0330.0600.0600.0660.0630.1620.0570.0300.1020.0900.0600.0630.060

0.069

0.030

0.162

0.030

45.22 40.000


-65-

Table A.6 TKN During First Stage

Sampl

Date

15-Oct17-Oct19-Oct22-Oct26-Oct30-Oct01-Nov03-Nov05-Nov08-Nov09-Nov11-Nov14-Nov18-Nov20-Nov23-Nov26-Nov30-Nov03-Dec06-Dec09-Dec

Average

Stand. 1

Maximum

Mini mum

Percent

Ing

Time

11:1.3:15:06:08:08:10:12:14:09:10:15:17:09:10:13:15:13:07:09:12:

Va

, hr

0000004500300000000030«45004545453030303030

lue

3eviation

Value

Value

Remova 1

FI

15.4813.9414.1717.4416.8615.8513.6910.4713.3814.1714.4213.2212.2415.2914.0315.0613.1615.7414.8414.2814.70

14.40

1.49

17.44

10.47

FIO

7.737.929.1311.7310.6410.089.168.887.899.309.078.629.588.799.329.529.1310.6411.5411.0611.06

9.56

1.14

11.73

7.73

33.61

7781110109879978899710101010

9

1

11

7

36

F30

.87

.56

.09

.09

.00

.25

.63

.76

.50

.27

.35

.50

.68

.90

.10

.41

.73

.53

.25

.78

.78

.19

.15

.09

.50

.18

F60

7.927.817.8110.2210.0210.029.978.998.299.278.767.988.298.999.359.588.6610.5310.3010.6410.50

9.23

0.95

10.64

7.81

35.88

TKN

Fe

7.257.648.799.8810.009.559.558.067.929.328.298.518-998.768.9010.198.099.189.8411.069.9¡i

9.03

0.94

11.06

7.25

37.29

(mg/L)

Hi

13.1614.2213.7216.2714.1716.6614.4511.8214.5613.6114.3414.7013.7815.4815.1815.7412.5415.1814.7313.8613.86

14.38

1.13

16.66

11.82

mo11.4210.8110.6712.8810.4212.0111.069.9410.8910.9511.1412.9412.0111.8212.5213.0712.3210.3012.7712.1812.46

11.65

0.94

13.07

9.94

18.98

H30

10.307.958.068. 128.2010.7810.509.7710.1910.259.2710.5610.7811.0911.8712.6910.9812.2111.8711.7611.34

10.41

1.38

12.69

7.95

27.61

H60

8.097.677.786.807.789-699.588.968.889.469.219.6310.7810.6711.0312.2610,9211.5911.5411.2010.92

9.74

1.49

12.26

6.80

32.27

He

6.947.087.007.147.957.648.489.078.018.708.709.109.949.7710.2511.7610.7511.6511.4811.0610.78

9.20

1.59.

11.76

6.94

36.02

-66-

Table A .7 To ta l Phosphorous During F i r s t Stage

Sampling

Date Time, hr

15-0ct 11:0017-0ct 13:0019-0ct 15:0022-0ct 06:1526-Oct 08:0030-0ct 08:3001-Nov 10:0003-Nov 12:0005-Nov 14:0008-Nov 09:3009-Nov 10:3011-Nov 15:4514-Nov 17:0018-Nov 09:4520-Nov 10:M523-Nov 13:4526-Nov 15:3030-Nov 13:3003-Dec 07:3006-Dec 09:3009-Dec 12:30

Average Va lue

Stand. Deviation

Maximum Va lue

Mint mum Va 1ue

Percent Removal

TP (mg/L)

Fi

2.282.162. 152.352.162.362.111.961.802. 122.272.122.672.572.672.082.162.101.832.162. 18

2.27

0.21

2.67

1.80

__

F10

1.611.601.912.272.072.112.332.011.762.182.312.052.372.422.081.892.082.121.822.132.10

2.06

0.22

2.12

1.60

9.25

F30

1.181.631.761.962.022.282.292.121.601.981.881.992.072.292.081.842.042.121.812.041.99

1.96

0.21

2.29

1.48

13.66

F60

1.561.591.801.901.892.132.392.101.621.911.992.002.162.111.931.862.012.081.812.102.08

1.95

0.20

2.39

1.56

14.10

Fe

1.461.631.711.812.192.072.131.901.602.161.841.992.242.121.861.951.991.891.822.081.95

1.93

0.20

2.24

1.46

14.98

HI

1.922.132.282.352. 112.422.592.081.902.082.312.452.542.612.372. 102.442.251.831.932.06

2.23

0.23

2.61

1.83

H10

1.862.092.202.511.762.022.371.981.641.952.132.262.412.502.522.072.292.211.912.162.01

2.14

0.24

2.52

1.64

4.04

H30

1.921.691.551.861.812.192.472.121.642.072.102.032.332.442.082.122.332.161.952.212.01

2-05

0.24

2.47

1.55

8.07

H60

1.521.551.501.621.802.042.402.101.662.052.162.262.412.542.232.142.422.211932.232.12

2.04

0.31

2.54

1.50

8.52

He

1.561.531-551.701.751.862.372.141.802.122.361.652.462.462.232.162.462.291.892.251.89

2.02

0.32

2.46

1.53 .

9.42

-67-

Tabte A.8 Dissolved Oxygen During First Stage

Satnpi ing

Date Time, hr

15-Oct 11:0017-Oct 13:0019-Oct 15:0022-Oct 06:14526-Oct 08:0030-Oct 08:3001-Nov 10:0003-Nov 12:0005-Nov 11:0008-Nov 09:0009-Nov 10:3011-Nov 15:4514-Nov 17:0018-Nov 09:4520-Nov 10:4523-Nov 13:4526-Nov 15:3030-Nov 13:3003-Dec 07:3006-Dec 09:3009-Dec 12:30

Average Va lue

Stand. Deviat ion

Maximum Va lue

M i n i mum Va 1ue

DO (mg/L)

FÎ

1.108.103.900.200.500.301.505.603.800.400.301.000.400.303.002.900.803.000.100.706.70

2.12

2.29

8.10

0.10

F10

6.2022.1026.200.401.601.708.50

11.8015.901.805.20

17.3015.907.10

11.1020.6020.9011».000.605.10

11.70

10.75

7.67

26.20

0.40

F30

9.9026.7026.60

0.401.602.508.40

12.9017.50

1.602.50

17.7016.MO8.00

13.9028.6022.«4019.100.705.00

11.50

12.09

8.97

28.60

0.40

F6O

10.5027.2025.100.501.402.506.50

15.5016.10

1.003.60

17.6015.208.90

13.7028.3021.0020.50

0.505.00

12.90

12.07

8.85

28.30

0.50

Fe

7.9022.2020.000.300.500.702.«408.40

11.201.501.50

14.2011.90«4.507.70

17,2013.4018.400.504.00

10.50

8.52

6.91

22.20

0.30

Hi

0.609.808.600.200.700.200.500.400.300.300.300.300.400.400.300.300.200.200.200.200.40

1.18

2.61

9.80

0.20

H10

0.300.401.000.700.800.501.000.600.600.600.500.400.500.700.600.900.600.300.400.400.50

0.59

0.20

1.00

0.30

H30

0.200.300.300.800.900.500.400.600.700.600.400.500.500.800.100.400.400.500.500.400.50

0.49

0. 19

0.90

0.10

H60

0.300.300.200.700.900.500.600.800.700.500.400.400.500.600.600.400.400.300.500.500.50

0.50

0.17

0.90

0.20

He

0.400.500.200.300.900.300.500.500.500.400.400.400.400.600.400.400.200.300.300.300.20

0.40

0.15

0.90

0.20

-68-

Table A,9 pH Value During First Stage

SamplIng

Date Time, hr

I5-Oct 11:0017-Oct 13:0019-Oct 15:0022-0ct 06:i<526-0ct 08:0030-0ct 08:3001-Nov 10:0003-Nov 12:0005-Nov 14:0008-Nov 09:0009-Nov 10:3011-Nov 15:4514-Nov 17:0018-Nov 09:4520-Nov 10:4523-Nov 13:4526-Nov 15:3030-Nov 13:3003-Dec 07:3006-Dec 09:3009-Dec 12:30

Average Value

Stand. Deviation

Maximum Va lue

Minimum Va lue

pH

Fi

7.558.207.907.507.557.607.608.057.507.457.507.607.507.457.657.857.557.707.407.557.90

7.65

0.21

8.20

7.40

F10

8.409.109.058.058.158.208.358.408.607.808.008.658.708.208.608.908.758.607.908.208.40

8.43

0.35

9.10

7.80

F30

8.609.209.008.158.108.258.408.508.707.857.908.658.558.258.658.958.808.807.958.258.45

8.47

0.36

9.20

7.85

F60|

8.659.209.008.258.108.308.408.558.607.807.958.658.508.308.608.908.708.858.008.258.50

8.48

0.35

9.20

7.80

Fe

8.509.108.708.208.108.308.208.408.507.907.908.558.308.108.558.658.708.858.008.308.60

8.40

0.31

9.10

7.90

Hi

7.708.157.857.757.557.507.557.557.507.307.407.507.307.357.707.757.457.807.507.507.90

7.60

0.21

8.15

7.30

H10

7.457.607.307.307.207.207.307.207.207.207.207.257.107.157.457.457.307.457.307.407.55

7.31

0.13

7.60

7.10

H30

7.457.507.207.257.107.207.257.157.157.157.157.207.057.107.457.457.307.407.307.407.50

7.27

0.14

7.50

7.05

H60

7.357.507.107.207.107.107.257.157.107.157.107.157.057.107.407.407.357.407.207.357.45

7.24

0.14

7.50

7.05

He

7.257.507.107.207.107.057.207.057.007.057.057.006.957.007.307.307.257.357.207.257.40

7.17

0.15

7.50

6.95

-69-

Tsble A.10 Temperature During F i rs t Stage

Sampling

Date Time, hr

15-0ct 11:0017-Oct 13:0019-Oct 15:0022-Oct 06:1526-Oct 08:0030-0ct 08:3001-Nov 10:0003-Nov 12:0005-Nov 11:0008-Nov 09:0009-Nov 10:3011-Nov 15:1511-Nov 17:0018-Nov 09:1520-Nov 10:1523-Nov 13:1526-Nov 15:3030-Nov 13:3003-Dec 07:3006-Dec 09:3009-Dec 12:30

Average Va lue

Stand, Deviation

Maximum Va 1ue

Mini mum Va 1ue

Temperature

Fi

31.7036.1033.9030.1029.7029.7030.1033.5031.1029.1029.5031.5030.0031.1031.5032.5032.0031.9025.1026.7026.80

30.70

2.15

36.10

25.10

F10

31.9036.3036.2030.8030.0029.8030.7032.2031.5029.3029.5031.9031.1031.3031.5032.9032.1030.8021.7025.3021.10

30.69

2.97

36.30

21.10

F30

32.1036.8035.8030.8029.9029.8030.5032.7031.5029.3029.1031.9031.0031.1031.8031.1032.3031.5021.8025.3021.10

30.83

3.07

36.80

21.10

F60

32.1036.5035.1030.8030.0029.8030.2033.1031.1029.2029.2032.0030.9031.7031.9033.7032.3031.7025.0025.3021.50

30.80

2.98

36.50

21.50

Fe

32.6035.1031.0030.9029.7029.7029.1033.3031.1029.2029.0031.8030.7030.1031.1032.1032.2032.2021.6025.1021.80

30.17

2.79

35.10

21.60

Hi

31.6036.2031. 3030.6030.0030.1030.0031.6031.1029.6029.6031.6030.7031.7031.3032.3032.1032.1025.9027.0027.10

30.81

2.21

36.20

25.90

H1O

29.7031.0030.9028.8028.2028.7028.1029.7029.0028.3028.1029.1028.9028.9029.3029.5029.6028.9025.0025.0021.00

28.52

1.75

31.00

21.00

H30

29.1031.0029.5028.3027.6028.1028.3029.9028.7027.9027.7028.7028.1028.5028.6028.9029.1028.0021.8021.1023.10

28.01

1.80

31.00

23.10

H60

29-1030.9029.1028.0027.1027.6028.0029.5028.6027.8027.6028.50.28.0028.3028.3028.7029.0027.7021.6021.2022.50

27.78

1.81

30.90

22.50

He

28.7029.2028.7028.0027.3027.1027.1028.2027.9027.5027.2028.0027.7028.0027.9028.1028.5027.7021.1021.0022.10

27.31

1.65

29.20

22.10

-70-

APPENDIX - B

EXPERIMENTAL DATA DURING SECOND STAGE

LABORATORY ANALYSIS REPORT OF DIFFERENT PARAMETERSMEASURED FOR WATER HYACINTH POND DURING SECOND STAGE

-71-

Table B.I BOD Value During Second Stage

Sampling

Date

12-Dec14-Dec16-Dec18-Dec20-Dec23-Dec25-Dec27-Dec29-Dec31-Dec02-Jan04-Jan06-Jan08-Jan10-Jan13-Jan16-Jan19-Jan22-Jan25-Jan28-Jan31-Jan04-Feb07-Feb10-Feb13-Feb16-Feb19-Feb22-Feb25-Feb28-Feb

Average

Stand. I

Maximum

Minimum

Percent

Time, hr

10:3017:0015:3011:3008:3010:3012:3007:3010:0011:0011:4513:0014:0015:0016:0017:0010:0010:3009:0012:3013:3015:0008:0017:0010:0014:0012:0016:0009:0011:0013:00

Value

)eviation

Value

Value

Removal

Inflow

72607154249582256767121108888491697610810199789335541201179280120115102

83

26

121

24

-

.00

.00

.25

.38

.80

.63

.50

.00

.50

.50

.87

.75

.13

.38

.00

.38

.88

.75

.25

.38

.75

.75

.62

.38

.00

.50

.15

.63

.00

.00

.86

.26

.26

.87

.80

--

Hi

50.54.55.53.45.47.48.44.42.45.47.43.55.55.51.49.48.47.48.50.52.50.55.52.48.45.55.59.45.52.60.

50.

4.

60

42

39

20700090408050103020900000000050009040804020108040750040005000

33

49

00

30

55

B0D5(mg/L)

H10

23.8019.8024.0019.8029.4022.2027.6027.0025.6021.0027.0020.4029.0033.0034.8030.0022.8025.2024.0020.4027.6029.4036.6026.4028.2025.2032.4037.1330.7535.0038.00

27.53

5.21

38.00

19.80

45.30

H30

16.13.17.14.16.20.24.28.17.17.21.16.22.24.27.24.20.21.24.19.22.23.30.19.25.20.29.32.25.30.30.

22

5

32

13

55

50000050000000005050000000500000000000405040000050505040007540

32

11

40

00

65

H60

10111312151618221817171520192121182023181920271521172524222827

19

4

28

10

61

.71

.29

.71

.86

.00

.71

.86

.70

.43

.57

.57

.86

.00

.29

.86

.86

.00

.57

.57

.30

.30

.15

.00

.00

.00

.00

.25

.50

.75

.80

.12

.44

.45

.80

.71

.38

He

9.10.10.12.11.13.18.17.13.15.17.14.17.16.17,18.17.17.15.17.17.19.22.22.20.1824.23.162223

17

3

24

9

65

80402000902000705060408070201000107000577050208070750073505030

18

94

00

80

87

Inflow = Anaerobic pond influent

-72-

Table B.2 Nitrite Nitrogen During Second Stage

Sampling

Date Time, hr

12-Dec 10:3014-Dec 17:0016-Dec 15:3018-Dec 11:3020-Dec 08:3023-Dec 10:3025-Dec 12:3027-Dec 07:3029-Dec 10:0031-Dec 11:0002-Jan 11:4504-Jan 13:0006-Jan 14:0008-Jan 15:0010-Jan 16:0013-Jan 17:0016-Jan 10:0019-Jan 10:3022-Jan 09:0025-Jan 12:3028-Jan 13:3031-Jan 15:0004-Feb 08:0007-Feb 17:0010-Feb 10:0013-Feb 14:0016-Feb 12:0019-Feb 16:0022-Feb 09:0025-Feb 11:0028-Feb 13:00

Average Value

Stand. Deviation

Maximum Value

Minimum Value

Percent Removal

Inflow

0.0090.0100.0110.0100.0150.0060.0130.0010.0100.0060.0060.0070.0060.0090.0070.0090.0100.0070.0060.0090.0140.0130.0030.0110.0100.0120.0100.0060.0070.0110.011

0.009

0.003

0.015

0.001

Hi

0.0110.0110.0130.0120.0070.0090.0180.0040.0100.0100.0090.0100.0110.0120.0120.0130.0120.0110.0120.0100.0190.0150.0160.0100.0160.0170.0220.0160.0250.0250.024

0.014

0.005

0.025

0.004

-55.56

NO2-h

H10

0.0080.0100.0090.0100.0070.0070.0110.0060.0090.0100.0100.0100.0100.0130.0120.0130.0120.0130.0100.0060.0130.0170.0190.0180.0110.0190.0210.0170.0250.0260.030

0.013

0.006

0.030

0.006

7.15

J (mg/D

H30

0.0110.0100.0130.0090.0040.0090.0090.0060.0080.0030.0140.0130.0060.0090.0080.017

•0.0140.0140.0150.0090.0160.0130.0280.0090.0160.0160.0220.0040.0290.0260.022

0.013

0.007

0.029

0.003

7.15

H60

0.0090.0070.0070.0070.0030.0150.0040.0060.0120.0040.0110.0080.0060.0080.0060.0170.0220.0150,0130.0110.0120.0110.0250.0060.0210.0120.0110.0080.0210.0200.028

0.012

0.006

0.028

0.003

14.28

He

0.0130.0140.0150.0140.0230.0170.0170.0090.0110.0150.0140.0160.0130.0130.0160.0200.0170.0160.0180.0160.0210.0220.0230.0230.0220.0230.0250.0210.0260.0220.030

0.018

0.005

0.030

0.009

-28.60



-73-

Table B.3 Nitrate Nitrogen During Second Stage

Sampling

Date Time, hr


Average Value

Stand. Deviation

Maximum Value

Minimum Value

Percent Removal

Inflow

0.0960.0390.0900.0720.0240.0900.0900.0270.0900.0600.1050.1050.0750.120

. 0.0750.0660.1410.0960.0960.0930.0750.1050.0540.0570.1350.1050.0990.0910.0930.0960,087

0.085

0.027

0.141

0.024

Hi

0.0660.0900.1170.0930.0600.0570.0720.0420.0780.0300.0270.0510.0870.0540.0390.0330.0450.0600.0450.0510.0600.0510.0480.0480.0390.0660.0660.0660.0600.0630.051

0.059

0.019

0.117

0.027

30.58

NO3-h

H10

0.0660.0570.0600.0510.0570.0270.0540.0510.0600.0300.0330.0540.0510.0540.0360.0360.0420.0570.0390.0420.0570.0480.0510.0450.0450.0600.0630.0570.0630.0450.057

0.050

0.010

0.066

0.027

15.25

J (mg/L)

H30

0.0870.0510.0660.0450.0630.0360.0480.0540.0420.0330.0390.0630.0600.0510.0360.0480.0510.0600.0420.0360.0630.0570.0450.0570.0510.0540.0660.0540.0570.0570.060

0.053

0.011

0.087

0.033

10.17

H60

0.0690.0420.0630.0450.0540.0210.0510.0420.0450.0330.0390.0570.0450.0450.0450.0360.0570.0660.0360.0570.0600.0540.0450.0570.0540.0570.0660.0510.0600.0480.057

0.050

0.011

0.069

0.021

15.25

He

0.0690.0390.0660.0540.0570.0120.0300.0570.0400.0330.0450.0540.0540.0480.0600.0360.0660.0600.0390.0390.0540.0540.0540.0510.0540.0570.0600.0540.0540.0420.057

0.050

0.012

0,069

0.012

15.25



-74-

Table B.4 Total Kjeldahl Nitrogen During Second Stage

Sampling

Date Time, hr


Average Value

Stand. Deviation

Maximum Value

Minimum Value

Percent Removal

TKN (mg/L)

Inflow

18.7618.0618.2019.995.60

19.8818.637.25

19.7416.6624.6417.2217.3618.2020.0219.4620.1619.6024.5020.1618.2016.249.80

16.5227.8616.8020.0217.2227.5821.2816.38

18.45

4.62

27,86

5.60

Hi

14.9815.2015.6815.2613.3014.2814.9813.5012.4613.3414.5012.1815.4015.9615.4014.5614.0014.0013.0214.4115.1016.6615.4016.5215.8216.6616.2416.9517.3616.9417.08

15.07

1.38

17.36

12.18

18.32

H10

11.2012.6014.8412.0412.3211.4812.4611.4811.3410.7813.0210.7812.4612.3212.7412.6012.4612.0411.7612.4612.6015.2618.7615.9614.5615.2614.1415.4014.8415.6814.70

13.24

1.82

18.76

10.78

12.14

H30

11.0610.6410.5011.7611.2011.9011.7611.4810.9210.5012.1810.5011.4811.7611.7611.2010.5011.4810.9212.0411.7014.8414.0014.1413.7214.8414.0013.7214.0015.1214.42

12.26

1.49

15.12

10.50

18.65

H60

10.5010.2010.6410.7811.3411.4811.7610.9010.5010.3410.5010.3610.7811.4810.6410.5010.2010.6410.5011.6211.2013,3013.7212.8813.7214.0013.3013.7213.5814.7014.14

11.74

1.44

14.70

10.20

22.10

He

10.369.66

10.2210.2210.6410.7810.6010.5010.089.949.38

10.2210.0811.2011.209.079.669.609.52

10.9210.0413,3012.1813.7212.3213.7213.3013.5812.7413.1613.72

11.15

1,51

13.72

9.07

26.01


-75-

Table B.5 Total Phosphorous During Second Stage

Sampling

Date

12-Dec14-Dec16-Dec18-Dec20-Dec23-Dec25-Dec27-Dec29-Dec31-Dec02-Jan04-Jan06-Jan08-Jan10-Jan13-Jan16-Jan19-Jan22-Jan25-Jan28-Jan31-Jan04-Feb07-Feb10-Feb13-Feb16-Feb19-Feb22-Feb25-Feb28-Feb

Average

Time, hr

10:3017:0015:3011:3008:3010:3012:3007:3010:0011:0011:4513:0014:0015:0016:0017:0010:0010:3009:0012:3013:3015:0008:0017:0010:0014:0012:0016:0009:0011:0013:00

Value

Stand. Deviation

Maximum

Minimum

Percent

Value

Value

Removal

Inflow

2.882.702.853.080.853.102.900.983.242.603.902.782.822.983.343.223.523.333.883.483.542.511.412.614.133.012.743.143.763.562.74

2.95

0.74

4.13

0.85

...

Hi

2.2.2.2.1.2.2.2.1.1.2.1.2.2.2.2.2.2.2.2.2.2.2.2.2.2.2.2.2.2.2.

2.

0.

2.

1.

23.

18212925991216109595108825351210141618204648384241694250185247

25

19

69

88

73

TP

H10

1.952.042.592.132.181.922.211.991.991.532.231.752.152.182.122.152.071.991.892.202.172.482.752.512.172.452.182.422.192.292.59

2.18

0.25

2.75

1.53

3.11

(mg/L)

H30

2.1.1.2.2.2.2.2.2.1.2.1.2.2.2.1.1.2.2.2.2.2.2.2.2.2.2.2.2.2.2.

2.

0.

2.

1.

6

03848612041411140883208003021295910601221140313527411729202330

11

16

41

80

22

H60

1.861.791.892.062.102.082.182.081.941.812.131.781.972.141.921.982.082.081.962.202.192.292.312.252.282.372.162.252.152.312.30

2.09

0.16

2.37

1.78

7.11

He

1.961.781.952.012.122.102.022.081.981.741.812.051.992.102.081.891.951.991.982.202.082.302.212.312.142.152.202.272.162.372.34

2.07

0.16

2.37

1.74

8.00


-76-

Table B.6 Dissolved Oxygen During Second Stage

Sampling

Date Time, hr

12-Dec 10:3014-Dec 17:0016-Dec 15:3018-Dec 11:3020-Dec 08:3023-Dec 10:3025-Dec 12:3027-Dec 07.-3029-Dec 10:0031-Dec 11:0002-Jan 11:4504-Jan 13:0006-Jan 14:0008-Jan 15:0010-Jan 16:0013-Jan 17:0016-Jan 10:0019-Jan 10:3022-Jan 09:0025-Jan 12:3028-Jan 13:3031-Jan 15:0004-Feb 08:0007-Feb 17:0010-Feb 10:0013-Feb 14:0016-Feb 12:0019-Feb 16:0022-Feb 09:0025-Feb 11:0028-Feb 13:00

Average Value

Stand. Deviation

Maximum Value

Minimum Value

DO (mg/L)

Inflow

0.200.200.300.200.200.100.200.100.200.300.300.400.200.300.200.400.100.200.300.300.300.200.300.200.200.300.300.200.200.200.20

0.24

0.07

0.40

0.10

Hi

0.200.200.200.200.200.200.200.100.200.200.200.300.200.200.200.300.200.200.300.400.200.200.200.300.300.200.200.200.200.200.20

0.22

0.05

0.40

0.10

H10

0.500.400.500.400.400.500.450.400.400.400.500.400.400.400.400.400.400.400.400.500.400.300.300.500.600.500.500.500.600.600.60

0.45

0.08

0.60

0.30

H30

0.400.300.500.300.400.400.400.500.300.300.300.300.400.300.400.300.300.300.400.400.500.200.300.500.500.400.500.400.500.500.50

0.39

0.09

0.50

0.20

H60

0.300.400.400.300.400.400.400.500.300.300.200.300.300.300.400.300.300.300.400.400.500.200.300.500.400.500.400.400.400.400.40

0.36

0.08

0.50

0.20

He

0.200.300.300.200.300.300.300.300.200.200.200.200.200.200.300.200.200.300.300.300.300.200.200.300.300.300.200.300.300.300.30

0.26

0.05

0.30

0.20

Inflow » Anaerobic pond influent

-77-

Table B.7 pH Value During Second Stage

Sampling

Date Time, hr


Average Value

Stand. Deviation

Maximum Value

Minimum Value

Inflow

7.607.557.457.607.557.707.607.507.607.607.507.607.607.507.607.607.707.607.707.557.407.607.457.607.607.557.607.507.507.507.50

7.56

0.07

7.70

7.40

Hi

7.407.607.557.507.507.507.507.407.507.457.407.507.457.507.507.507.557.507.557.457.507.507.507.407.407.407.357.407.407.407.30

7.46

0.07

7.60

7.30

pF

H10

7.257.407.407.407.407.357.407.357.407.407.307.457.357.357.407.407.457.357.407.357.457.407.407,307.357.307.307.307.307.357.25

7.36

0.05

7.45

7.25

[

H30

7.257.407.357.407.407.357.407.307.407.407.307.407.357.357.407.407.407.357.407.307.407.407.407.307.357.307.307.307.207.357.25

7.35

0.06

7.40

7.20

H60

7.257.357.307.357.357.307.357.307.357.407.307.307.307.307.407.357.407.307.357.307.407.307.307.307.307.257.307.207.207.307.20

7.31

0.05

7.40

7.20

He

7.207.257.207.207.257.2Ó7.307.207.307.307.257.207.257.207.307.307.307.207.257.207.307.207.257.207.257.207.207.107.157.207.10

7.23

0.05

7.30

7.10


-78-

Table B.8 Temperature During Second Stage

Sampling

Date Time, hr


Average Value

Stand, Deviation

Maximum Value

Minimum Value

Temperature °C

Inflow

29.2029.1029.4028.5027.5028.0028.2028.5029.3029.3029.1029.2029.8029.5029.4029.6029.5029.5029.1030.0030.4030.6029.4030.5030.3030.7030.4030.2029.9030.7031.00

29.54

0.83

31.00

27.50

Hi

28.3030.1030.1028.0025.4026.8027.9026.4028.3028.9029.7029.7030.2030.3030.2030.0029.0029.0028.3030.1031.0030.9029.1030.4029.5030.4030.2029.9028.8030.0030.40

29.27

1.31

31.00

25.40

H10

25.3026.8026.5025.3023.8024.10•24.6024.5025.7026.3026.4026.1026.7027.2027.1027.3026.8026.8026.1027.6028.6028.8027.9028.7028.3029.0028.6028.2027.2028.2029.00

26.89

1.46

29.00

23.80

H30

24.6025.9025.7024.6023.2023.1023.8024.0025.3025.7025.3025.2025.8026.2026.2026.7026.2026.4025.7027.0028.2028.6027.6028.4028.0028.3028.2027.7026.7027.9028.50

26.28

1.58

28.60

23.10

H60

24.2025.5025.2024.1023.0022.8023.1023.8025.1025.4024.8024.7025.4025.8025.8026.1025.8025.9025.4026.8028.0028.2027.5028.1027.7028.1027.9027.5026.5027.6028.30

25.94

1.63

28.30

22.80

He

23.7024.8024.8023.8022.8022.6022.8023.3024.6025.0024.6024.4024.9025.2025.3025.6025.7025.7025.2026.4027.6027.8027.2027.6027.5027.8027.8027.2026.2027.4027.90

25.59

1.64

27.90

22.60

Inflow » Anaerobic pond influent

-79-

APPENDIX C

FLOW RATE OF THE PONDS DURING FIRST AND SECOND STAGE

-80-

Table C.I Flow rate (m3/d) for facultative and waterhyacinth pond during first stage

Date

1.11.872.11.873.11.874.11.875.11.876.11.877.11.878.11.879.11.8710.11.8711.11.8712.11.8713.11.8714.11.8715.11.8716.11.8717.11.8718.11.8719.11.8720.11.8721.11.8722.11.8723.11.8724.11.8725.11.8726.11.8727.11.87

Average Va lue

Fi

464.94505.72543.12504.82488.16445.54451.22527.79513.34527.06503.28495-59494.90476.36484.00496.95475.55456.84473.27485.05474-44423.80443.57443.78__

--

483.30

Hi

522.38482.31435.11439.81498.47496.62450.75440.75425.73447.30453.35460.31450.23446.11462.58481.23459.68451.63444.86466.32524.15491.15477.45446.03480.52475.14

465.77

Fe

_ .

411.98420.31395.23376.02352.82407.85400.84392.39417.41407.25396.22380.25370.63369.61410.76395.35376.27358.91368.16359.74350.30364.07350.04416.60385.24381.92

385.24

He

__--

460.47387.49363.87411.04435.03382.11362.44346.19385.93374.32385.26380.37361.79375.32390.49383.41373.96364.93379.58424.20406.14390.50------

387.49

-81-

Table C.2 Flow rate (m3/d) insecond stage

Water Hyacinth Pond during

Date

11.12.8712.12.8713.12.8714.12.8715.12.8716.12.8717.12.8718.12.8719.12.8720.12.8721.12.8722.12.8723.12.8724.12.8725.12.8726.12.8727.12.8728.12.8729.12.8730.12.8731.12.871.1.882.1.883.1.884.1.885.1.886.1.887.1.888.1.889.1.8810.1.8811.1.8812.1.8813.1.8814.1.8815.1.8816.1.8817.1.8818.1.88

Hi

868.41861.93765.96888.66873.38883.39896.98874.29858.44802.34843.64885.78868.96867.56856.09831.97781.64818.97822.11790.63775.26721.27786.56828.52861.51801.92896.82872.33861.72850.50875.39919.76907.01938.50927.60214.66950.45890.30915.25

839.40

He

676.87646.93611.21636.81623.79685.01641.39580.67562.27509.65523.07554.45590.70554.45544.30533.46509.41501.88505.56530.73518.03499.11499.90511.29540.53543.35622.31629.25603.88564.38552.42667.03687.07669.99627.83344.22425.60639.48621.69

571.54

Date

19.1.8820.1.8821.1.8822.1.8823.1.8824.1.8825.1.8826.1.8827.1.8828.1.8829.1.8830.1.8831.1.881.2.882.2.883.2.884.2.885.2.886.2.887.2.888.2.889.2.8810.2.8811.2.8812.2.8813.2.8814.2.8815.2.8816.2.8817.2.8818.2.8819.2.8820.2.8821.2.8822.2.8823.2.8824.2.8825.2.88 .26.2.88

Hi

886.36872.44--

840.86532.36885.74______----__----

844.86836.56924.12838.23829.64799.44801.88865.95912.82825.22798.15822.35. _-.--__

915.12862.21845.74854.10868.77806.93856.19827.17848.18858.15

839.24

He

635.44618.95598.68601.43429.55581.12597.75591.86581.17576.44589.87614.65578.84596.46618.26604.24624.67611.55586.86576.40581.22597.54612.25609.77587.41574.22579.55546.34538.87598.80608.45601.65581.56564.72547.66573.16------

586.59

Average Influent Flow = 839.32 (m3/d)Average Effluent Flow = 579.07 (m3/d)

IRC · EV-REMOVAL OF NITROGEN AND PHOSPHOROUS IN A FACULTATIVE AND A WATER HYACINTH POND: A CASE...

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Transcript of IRC · EV-REMOVAL OF NITROGEN AND PHOSPHOROUS IN A FACULTATIVE AND A WATER HYACINTH POND: A CASE...